📐 Geometry

Read this aloud (it is the lesson's hook). Students think, then tell a partner what they notice.

“With only a compass and a straightedge, builders long ago drew perfect shapes.”

1. Open the lesson link on the board.
2. Press Next to the 🎬 Watch in 3D step and press ▶ Play. Students can drag to turn the model. This lesson has 2 3D videos in a row: press Next and ▶ Play for each part.
3. Press Next to the Movie step and press ▶ Play.

The video says:

• Geometry starts with undefined terms. A point is an exact location, with no size.
• A line goes on forever in both directions. Two points name it: line A B.
• A plane is a flat surface that goes on forever, like a floor without edges.
• An angle is two rays that share one endpoint, the vertex.

Students open the same lesson on their own device (or work with the board). Press Next to Try it.

Try it together first:

🧱 Build it: the lesson's short 3D build game. Let students play it after Try it. Its score never changes grades.

If time is left, students play the lesson's game steps (they show up between the videos and Check).

Students press Next to Check and answer the 4 questions on their own device. Goal: 100%. 95% or more is Mastered. “Not yet” means try again; students may retry.

Read this question aloud. Students write the answer on a slip of paper with no name or with a class number, and hand it in.

Read this aloud (it is the lesson's hook). Students think, then tell a partner what they notice.

“Find the exact middle of a beam, or draw a perfect hexagon, with no ruler numbers.”

1. Open the lesson link on the board.
2. Press Next to the 🎬 Watch in 3D step and press ▶ Play. Students can drag to turn the model. This lesson has 3 3D videos in a row: press Next and ▶ Play for each part.
3. Press Next to the Movie step and press ▶ Play.

The video says:

• Find the exact middle of a beam, segment A B, with no ruler numbers.
• Open the compass more than halfway. From A, draw arcs above and below.
• Same width from B. The arcs cross in two points.
• A line through the two crossings is the perpendicular bisector. It meets A B at its midpoint, at a right angle.

Students open the same lesson on their own device (or work with the board). Press Next to Try it.

Try it together first:

🧱 Build it: the lesson's short 3D build game. Let students play it after Try it. Its score never changes grades.

If time is left, students play the lesson's game steps (they show up between the videos and Check).

Students press Next to Check and answer the 4 questions on their own device. Goal: 100%. 95% or more is Mastered. “Not yet” means try again; students may retry.

Read this question aloud. Students write the answer on a slip of paper with no name or with a class number, and hand it in.

Read this aloud (it is the lesson's hook). Students think, then tell a partner what they notice.

“Slide, flip, turn: the shape moves but keeps its size and shape.”

1. Open the lesson link on the board.
2. Press Next to the 🎬 Watch in 3D step and press ▶ Play. Students can drag to turn the model. This lesson has 2 3D videos in a row: press Next and ▶ Play for each part.
3. Press Next to the Movie step and press ▶ Play.

The video says:

• Triangle A B C. Rigid motions move it but keep its size and shape.
• Translation: slide every point 3 right and 2 down.
• Reflection over the y-axis: flip it like a page. Each point lands the same distance on the other side.
• Rotation 90 degrees counterclockwise about the origin: turn it.
• Every image is congruent to the original: same side lengths, same angles.

Students open the same lesson on their own device (or work with the board). Press Next to Try it.

Try it together first:

🧱 Build it: the lesson's short 3D build game. Let students play it after Try it. Its score never changes grades.

If time is left, students play the lesson's game steps (they show up between the videos and Check).

Students press Next to Check and answer the 4 questions on their own device. Goal: 100%. 95% or more is Mastered. “Not yet” means try again; students may retry.

Read this question aloud. Students write the answer on a slip of paper with no name or with a class number, and hand it in.

Read this aloud (it is the lesson's hook). Students think, then tell a partner what they notice.

“A pizza cut into 8 equal slices looks the same after a 45° turn.”

1. Open the lesson link on the board.
2. Press Next to the 🎬 Watch in 3D step and press ▶ Play. Students can drag to turn the model. This lesson has 2 3D videos in a row: press Next and ▶ Play for each part.
3. Press Next to the Movie step and press ▶ Play.

The video says:

• A square. Turn it 90 degrees about its center. It lands exactly on itself.
• 180 and 270 degrees also work. A square has turns of 90, 180 and 270 degrees.
• A regular pentagon: the smallest turn is 360 divided by 5, which is 72 degrees.
• For a regular n-gon, the smallest turn is 360 divided by n.

Students open the same lesson on their own device (or work with the board). Press Next to Try it.

Try it together first:

🧱 Build it: the lesson's short 3D build game. Let students play it after Try it. Its score never changes grades.

If time is left, students play the lesson's game steps (they show up between the videos and Check).

Students press Next to Check and answer the 4 questions on their own device. Goal: 100%. 95% or more is Mastered. “Not yet” means try again; students may retry.

Read this question aloud. Students write the answer on a slip of paper with no name or with a class number, and hand it in.

Read this aloud (it is the lesson's hook). Students think, then tell a partner what they notice.

“Game moves: slide, then flip. The order can change where the shape ends up.”

1. Open the lesson link on the board.
2. Press Next to the 🎬 Watch in 3D step and press ▶ Play. Students can drag to turn the model. This lesson has 2 3D videos in a row: press Next and ▶ Play for each part.
3. Press Next to the Movie step and press ▶ Play.

The video says:

• Start with a triangle whose corner is at 1, 3.
• Move 1: translate right 2. A goes from 1, 3 to 3, 3.
• Move 2: reflect over the x-axis. 3, 3 goes to 3, negative 3.
• Any chain of rigid motions keeps the size and shape, so the final image is congruent.

Students open the same lesson on their own device (or work with the board). Press Next to Try it.

Try it together first:

🧱 Build it: the lesson's short 3D build game. Let students play it after Try it. Its score never changes grades.

If time is left, students play the lesson's game steps (they show up between the videos and Check).

Students press Next to Check and answer the 4 questions on their own device. Goal: 100%. 95% or more is Mastered. “Not yet” means try again; students may retry.

Read this question aloud. Students write the answer on a slip of paper with no name or with a class number, and hand it in.

Read this aloud (it is the lesson's hook). Students think, then tell a partner what they notice.

“Railroad tracks and a road crossing them make matching angles.”

1. Open the lesson link on the board.
2. Press Next to the 🎬 Watch in 3D step and press ▶ Play. Students can drag to turn the model. This lesson has 2 3D videos in a row: press Next and ▶ Play for each part.
3. Press Next to the Movie step and press ▶ Play.

The video says:

• Two parallel lines, like railroad tracks, and a transversal road crossing them.
• The crossing makes 8 angles. Angle 1 is 65 degrees.
• Vertical angles, across from each other, are equal: angle 3 is also 65.
• Corresponding angles, in matching corners, are equal. Alternate interior angles, in a Z, are equal.
• Same-side interior angles add to 180: 65 plus 115.

Students open the same lesson on their own device (or work with the board). Press Next to Try it.

Try it together first:

🧱 Build it: the lesson's short 3D build game. Let students play it after Try it. Its score never changes grades.

If time is left, students play the lesson's game steps (they show up between the videos and Check).

Students press Next to Check and answer the 4 questions on their own device. Goal: 100%. 95% or more is Mastered. “Not yet” means try again; students may retry.

Read this question aloud. Students write the answer on a slip of paper with no name or with a class number, and hand it in.

Read this aloud (it is the lesson's hook). Students think, then tell a partner what they notice.

“A proof is a chain: each step has a reason.”

1. Open the lesson link on the board.
2. Press Next to the 🎬 Watch in 3D step and press ▶ Play. Students can drag to turn the model. This lesson has 3 3D videos in a row: press Next and ▶ Play for each part.
3. Press Next to the Movie step and press ▶ Play.

The video says:

• Two triangles with three pairs of equal sides: the tick marks match.
• A rigid motion, here a reflection, carries one exactly onto the other. So they are congruent.
• Shortcuts that prove congruence: S S S, S A S, A S A, A A S, and H L for right triangles.
• The three angles of any triangle add to 180 degrees: 50 plus 60 plus 70.

Students open the same lesson on their own device (or work with the board). Press Next to Try it.

Try it together first:

🧱 Build it: the lesson's short 3D build game. Let students play it after Try it. Its score never changes grades.

If time is left, students play the lesson's game steps (they show up between the videos and Check).

Students press Next to Check and answer the 4 questions on their own device. Goal: 100%. 95% or more is Mastered. “Not yet” means try again; students may retry.

Read this question aloud. Students write the answer on a slip of paper with no name or with a class number, and hand it in.

Read this aloud (it is the lesson's hook). Students think, then tell a partner what they notice.

“Connect the midpoints of a triangle's sides and you get a smaller triangle with half-length sides.”

1. Open the lesson link on the board.
2. Press Next to the 🎬 Watch in 3D step and press ▶ Play. Students can drag to turn the model. This lesson has 2 3D videos in a row: press Next and ▶ Play for each part.
3. Press Next to the Movie step and press ▶ Play.

The video says:

• A triangle with base 18. Mark the midpoints of the other two sides.
• Join them: the midsegment M N. It is parallel to the base.
• And it is half as long: 18 divided by 2 is 9.

Students open the same lesson on their own device (or work with the board). Press Next to Try it.

Try it together first:

🧱 Build it: the lesson's short 3D build game. Let students play it after Try it. Its score never changes grades.

If time is left, students play the lesson's game steps (they show up between the videos and Check).

Students press Next to Check and answer the 4 questions on their own device. Goal: 100%. 95% or more is Mastered. “Not yet” means try again; students may retry.

Read this question aloud. Students write the answer on a slip of paper with no name or with a class number, and hand it in.

Read this aloud (it is the lesson's hook). Students think, then tell a partner what they notice.

“Where should a fountain go so it is the same distance from three classrooms? At the circumcenter.”

1. Open the lesson link on the board.
2. Press Next to the 🎬 Watch in 3D step and press ▶ Play. Students can drag to turn the model. This lesson has 2 3D videos in a row: press Next and ▶ Play for each part.
3. Press Next to the Movie step and press ▶ Play.

The video says:

• Three classrooms at A, B and C. Where should a fountain go so it is the same distance from all three?
• Draw the perpendicular bisector of each side.
• They meet at one point, the circumcenter.
• A circle centered there passes through all three corners. Each radius is the same distance.

Students open the same lesson on their own device (or work with the board). Press Next to Try it.

Try it together first:

🧱 Build it: the lesson's short 3D build game. Let students play it after Try it. Its score never changes grades.

If time is left, students play the lesson's game steps (they show up between the videos and Check).

Students press Next to Check and answer the 4 questions on their own device. Goal: 100%. 95% or more is Mastered. “Not yet” means try again; students may retry.

Read this question aloud. Students write the answer on a slip of paper with no name or with a class number, and hand it in.

Read this aloud (it is the lesson's hook). Students think, then tell a partner what they notice.

“A folding gate keeps its opposite sides parallel as it moves.”

1. Open the lesson link on the board.
2. Press Next to the 🎬 Watch in 3D step and press ▶ Play. Students can drag to turn the model. This lesson has 2 3D videos in a row: press Next and ▶ Play for each part.
3. Press Next to the Movie step and press ▶ Play.

The video says:

• A parallelogram: both pairs of opposite sides are parallel.
• Opposite sides are congruent: the tick marks match.
• Opposite angles are equal. Consecutive angles add to 180 degrees.
• The diagonals bisect each other: they cut each other in half at the same midpoint.

Students open the same lesson on their own device (or work with the board). Press Next to Try it.

Try it together first:

🧱 Build it: the lesson's short 3D build game. Let students play it after Try it. Its score never changes grades.

If time is left, students play the lesson's game steps (they show up between the videos and Check).

Students press Next to Check and answer the 4 questions on their own device. Goal: 100%. 95% or more is Mastered. “Not yet” means try again; students may retry.

Read this question aloud. Students write the answer on a slip of paper with no name or with a class number, and hand it in.

Read this aloud (it is the lesson's hook). Students think, then tell a partner what they notice.

“A phone zoom or a photo enlargement is a dilation.”

1. Open the lesson link on the board.
2. Press Next to the 🎬 Watch in 3D step and press ▶ Play. Students can drag to turn the model. This lesson has 2 3D videos in a row: press Next and ▶ Play for each part.
3. Press Next to the Movie step and press ▶ Play.

The video says:

• A small triangle and the center of dilation at the origin.
• Scale factor 3: multiply every coordinate by 3. The point 1, 1 goes to 3, 3, and 3, 1 goes to 9, 3.
• Every length triples, and every angle stays the same. The image is similar.
• The scale factor k is always positive. Between 0 and 1 it shrinks: k equals one half.

Students open the same lesson on their own device (or work with the board). Press Next to Try it.

Try it together first:

🧱 Build it: the lesson's short 3D build game. Let students play it after Try it. Its score never changes grades.

If time is left, students play the lesson's game steps (they show up between the videos and Check).

Students press Next to Check and answer the 4 questions on their own device. Goal: 100%. 95% or more is Mastered. “Not yet” means try again; students may retry.

Read this question aloud. Students write the answer on a slip of paper with no name or with a class number, and hand it in.

Read this aloud (it is the lesson's hook). Students think, then tell a partner what they notice.

“Use a shadow to measure a flagpole: similar triangles share ratios.”

1. Open the lesson link on the board.
2. Press Next to the 🎬 Watch in 3D step and press ▶ Play. Students can drag to turn the model. This lesson has 2 3D videos in a row: press Next and ▶ Play for each part.
3. Press Next to the Movie step and press ▶ Play.

The video says:

• A 6 foot person casts a 4 foot shadow.
• At the same moment, a flagpole casts a 20 foot shadow. The sun's rays make the same angle.
• Set up a proportion: height over shadow. 6 over 4 equals h over 20.
• h equals 6 times 20 over 4: 30 feet.

Students open the same lesson on their own device (or work with the board). Press Next to Try it.

Try it together first:

🧱 Build it: the lesson's short 3D build game. Let students play it after Try it. Its score never changes grades.

If time is left, students play the lesson's game steps (they show up between the videos and Check).

Students press Next to Check and answer the 4 questions on their own device. Goal: 100%. 95% or more is Mastered. “Not yet” means try again; students may retry.

Read this question aloud. Students write the answer on a slip of paper with no name or with a class number, and hand it in.

Read this aloud (it is the lesson's hook). Students think, then tell a partner what they notice.

“A line parallel to one side of a triangle cuts the other two sides in the same ratio.”

1. Open the lesson link on the board.
2. Press Next to the 🎬 Watch in 3D step and press ▶ Play. Students can drag to turn the model. This lesson has 2 3D videos in a row: press Next and ▶ Play for each part.
3. Press Next to the Movie step and press ▶ Play.

The video says:

• A line parallel to one side of a triangle cuts the other two sides.
• It cuts them in the same ratio: 4 to 6 on one side, 6 to x on the other.
• Cross multiply: 4x equals 36, so x equals 9.

Students open the same lesson on their own device (or work with the board). Press Next to Try it.

Try it together first:

🧱 Build it: the lesson's short 3D build game. Let students play it after Try it. Its score never changes grades.

If time is left, students play the lesson's game steps (they show up between the videos and Check).

Students press Next to Check and answer the 4 questions on their own device. Goal: 100%. 95% or more is Mastered. “Not yet” means try again; students may retry.

Read this question aloud. Students write the answer on a slip of paper with no name or with a class number, and hand it in.

Read this aloud (it is the lesson's hook). Students think, then tell a partner what they notice.

“A ramp, a ladder, a kite string: trig finds missing sides and angles.”

1. Open the lesson link on the board.
2. Press Next to the 🎬 Watch in 3D step and press ▶ Play. Students can drag to turn the model. This lesson has 3 3D videos in a row: press Next and ▶ Play for each part.
3. Press Next to the Movie step and press ▶ Play.

The video says:

• A right triangle with legs 3 and 4 and hypotenuse 5. Stand at angle A.
• From A: the side across is opposite, 3. The side touching A is adjacent, 4. The longest side, across from the right angle, is the hypotenuse, 5.
• Sine is opposite over hypotenuse: 3 over 5. Cosine is adjacent over hypotenuse: 4 over 5. Tangent is opposite over adjacent: 3 over 4.
• The ratios depend only on the angle. A bigger triangle with the same angle has the same ratios.

Students open the same lesson on their own device (or work with the board). Press Next to Try it.

Try it together first:

🧱 Build it: the lesson's short 3D build game. Let students play it after Try it. Its score never changes grades.

If time is left, students play the lesson's game steps (they show up between the videos and Check).

Students press Next to Check and answer the 4 questions on their own device. Goal: 100%. 95% or more is Mastered. “Not yet” means try again; students may retry.

Read this question aloud. Students write the answer on a slip of paper with no name or with a class number, and hand it in.

Read this aloud (it is the lesson's hook). Students think, then tell a partner what they notice.

“Standing 50 ft from a tree, you look up at its top. Trig finds its height.”

1. Open the lesson link on the board.
2. Press Next to the 🎬 Watch in 3D step and press ▶ Play. Students can drag to turn the model. This lesson has 2 3D videos in a row: press Next and ▶ Play for each part.
3. Press Next to the Movie step and press ▶ Play.

The video says:

• You stand 50 feet from a tree and look up at its top.
• The angle of elevation is measured up from the horizontal: 30 degrees.
• Height is opposite, 50 feet is adjacent: tangent. h over 50 equals tangent of 30.
• h equals 50 times tangent of 30: about 28.9 feet. This picture measures from the ground; add eye height if needed.

Students open the same lesson on their own device (or work with the board). Press Next to Try it.

Try it together first:

🧱 Build it: the lesson's short 3D build game. Let students play it after Try it. Its score never changes grades.

If time is left, students play the lesson's game steps (they show up between the videos and Check).

Students press Next to Check and answer the 4 questions on their own device. Goal: 100%. 95% or more is Mastered. “Not yet” means try again; students may retry.

Read this question aloud. Students write the answer on a slip of paper with no name or with a class number, and hand it in.

Read this aloud (it is the lesson's hook). Students think, then tell a partner what they notice.

“Prove a shape is a parallelogram using slopes and distances.”

1. Open the lesson link on the board.
2. Press Next to the 🎬 Watch in 3D step and press ▶ Play. Students can drag to turn the model. This lesson has 2 3D videos in a row: press Next and ▶ Play for each part.
3. Press Next to the Movie step and press ▶ Play.

The video says:

• How far is it from 1, 2 to 4, 6?
• Run, the change in x, is 3. Rise, the change in y, is 4.
• The distance is the hypotenuse: the square root of 3 squared plus 4 squared, which is 5.

Students open the same lesson on their own device (or work with the board). Press Next to Try it.

Try it together first:

🧱 Build it: the lesson's short 3D build game. Let students play it after Try it. Its score never changes grades.

If time is left, students play the lesson's game steps (they show up between the videos and Check).

Students press Next to Check and answer the 4 questions on their own device. Goal: 100%. 95% or more is Mastered. “Not yet” means try again; students may retry.

Read this question aloud. Students write the answer on a slip of paper with no name or with a class number, and hand it in.

Read this aloud (it is the lesson's hook). Students think, then tell a partner what they notice.

“Prove a shape is a rectangle using only its corner coordinates.”

1. Open the lesson link on the board.
2. Press Next to the 🎬 Watch in 3D step and press ▶ Play. Students can drag to turn the model. This lesson has 2 3D videos in a row: press Next and ▶ Play for each part.
3. Press Next to the Movie step and press ▶ Play.

The video says:

• A at 0, 0; B at 4, 0; C at 4, 3; D at 0, 3. Prove A B C D is a rectangle.
• Opposite sides are parallel: A B and D C have slope 0; A D and B C are vertical. So it is a parallelogram.
• Horizontal meets vertical: a right angle. A parallelogram with a right angle is a rectangle.
• Check the diagonals: A C and B D are both 5. Congruent diagonals, as a rectangle should have.

Students open the same lesson on their own device (or work with the board). Press Next to Try it.

Try it together first:

🧱 Build it: the lesson's short 3D build game. Let students play it after Try it. Its score never changes grades.

If time is left, students play the lesson's game steps (they show up between the videos and Check).

Students press Next to Check and answer the 4 questions on their own device. Goal: 100%. 95% or more is Mastered. “Not yet” means try again; students may retry.

Read this question aloud. Students write the answer on a slip of paper with no name or with a class number, and hand it in.

Read this aloud (it is the lesson's hook). Students think, then tell a partner what they notice.

“Place a bus stop 1/3 of the way from home to school on a map grid.”

1. Open the lesson link on the board.
2. Press Next to the 🎬 Watch in 3D step and press ▶ Play. Students can drag to turn the model. This lesson has 2 3D videos in a row: press Next and ▶ Play for each part.
3. Press Next to the Movie step and press ▶ Play.

The video says:

• Home is at 0, 0 and school is at 9, 6. Put a bus stop one third of the way.
• Ratio 1 to 2 means 3 equal parts in all. k is 1 over 1 plus 2: one third.
• x equals 0 plus one third of 9: 3. y equals 0 plus one third of 6: 2. The stop is at 3, 2.

Students open the same lesson on their own device (or work with the board). Press Next to Try it.

Try it together first:

🧱 Build it: the lesson's short 3D build game. Let students play it after Try it. Its score never changes grades.

If time is left, students play the lesson's game steps (they show up between the videos and Check).

Students press Next to Check and answer the 4 questions on their own device. Goal: 100%. 95% or more is Mastered. “Not yet” means try again; students may retry.

Read this question aloud. Students write the answer on a slip of paper with no name or with a class number, and hand it in.

Read this aloud (it is the lesson's hook). Students think, then tell a partner what they notice.

“Circles have arcs, chords, tangents and their own equation.”

1. Open the lesson link on the board.
2. Press Next to the 🎬 Watch in 3D step and press ▶ Play. Students can drag to turn the model. This lesson has 2 3D videos in a row: press Next and ▶ Play for each part.
3. Press Next to the Movie step and press ▶ Play.

The video says:

• The equation x minus 2, squared, plus y plus 1, squared, equals 49.
• Center h, k: here 2, negative 1. Watch the signs: plus 1 means k is negative 1.
• r squared is 49, so the radius is 7.
• Every point on the circle is exactly 7 from the center, like 2, 6 at the top.

Students open the same lesson on their own device (or work with the board). Press Next to Try it.

Try it together first:

🧱 Build it: the lesson's short 3D build game. Let students play it after Try it. Its score never changes grades.

If time is left, students play the lesson's game steps (they show up between the videos and Check).

Students press Next to Check and answer the 4 questions on their own device. Goal: 100%. 95% or more is Mastered. “Not yet” means try again; students may retry.

Read this question aloud. Students write the answer on a slip of paper with no name or with a class number, and hand it in.

Read this aloud (it is the lesson's hook). Students think, then tell a partner what they notice.

“A bike chain wrapping a gear and the spokes of a wheel obey circle angle rules.”

1. Open the lesson link on the board.
2. Press Next to the 🎬 Watch in 3D step and press ▶ Play. Students can drag to turn the model. This lesson has 2 3D videos in a row: press Next and ▶ Play for each part.
3. Press Next to the Movie step and press ▶ Play.

The video says:

• A chord joins two points on a circle. Two chords cross at a point inside.
• One chord is cut into 3 and 8. The other into 4 and x.
• Part times part equals part times part: 3 times 8 equals 4 times x. 24 equals 4x, so x is 6.

Students open the same lesson on their own device (or work with the board). Press Next to Try it.

Try it together first:

🧱 Build it: the lesson's short 3D build game. Let students play it after Try it. Its score never changes grades.

If time is left, students play the lesson's game steps (they show up between the videos and Check).

Students press Next to Check and answer the 4 questions on their own device. Goal: 100%. 95% or more is Mastered. “Not yet” means try again; students may retry.

Read this question aloud. Students write the answer on a slip of paper with no name or with a class number, and hand it in.

Read this aloud (it is the lesson's hook). Students think, then tell a partner what they notice.

“A pizza slice is a sector; its crust is an arc.”

1. Open the lesson link on the board.
2. Press Next to the 🎬 Watch in 3D step and press ▶ Play. Students can drag to turn the model. This lesson has 2 3D videos in a row: press Next and ▶ Play for each part.
3. Press Next to the Movie step and press ▶ Play.

The video says:

• A pizza with radius 6. Cut a 90 degree slice: a sector.
• The crust of the slice is an arc. It is 90 over 360 of the whole circumference: one fourth of 12 pi, which is 3 pi.
• The slice's area is one fourth of pi r squared: one fourth of 36 pi, which is 9 pi.

Students open the same lesson on their own device (or work with the board). Press Next to Try it.

Try it together first:

🧱 Build it: the lesson's short 3D build game. Let students play it after Try it. Its score never changes grades.

If time is left, students play the lesson's game steps (they show up between the videos and Check).

Students press Next to Check and answer the 4 questions on their own device. Goal: 100%. 95% or more is Mastered. “Not yet” means try again; students may retry.

Read this question aloud. Students write the answer on a slip of paper with no name or with a class number, and hand it in.

Read this aloud (it is the lesson's hook). Students think, then tell a partner what they notice.

“How much water fits in a cylinder tank? Volume tells you.”

1. Open the lesson link on the board.
2. Press Next to the 🎬 Watch in 3D step and press ▶ Play. Students can drag to turn the model. This lesson has 2 3D videos in a row: press Next and ▶ Play for each part.
3. Press Next to the Movie step and press ▶ Play.

The video says:

• A cylinder tank with radius 3 and height 10.
• Volume is pi r squared h: pi times 9 times 10, which is 90 pi, about 282.7 cubic units.
• A cone with the same radius and height holds one third as much: 30 pi.
• Watch: three cones of water fill the cylinder.

Students open the same lesson on their own device (or work with the board). Press Next to Try it.

Try it together first:

🧱 Build it: the lesson's short 3D build game. Let students play it after Try it. Its score never changes grades.

If time is left, students play the lesson's game steps (they show up between the videos and Check).

Students press Next to Check and answer the 4 questions on their own device. Goal: 100%. 95% or more is Mastered. “Not yet” means try again; students may retry.

Read this question aloud. Students write the answer on a slip of paper with no name or with a class number, and hand it in.

Read this aloud (it is the lesson's hook). Students think, then tell a partner what they notice.

“Push a stack of coins into a slant: it still has the same volume.”

1. Open the lesson link on the board.
2. Press Next to the 🎬 Watch in 3D step and press ▶ Play. Students can drag to turn the model. This lesson has 2 3D videos in a row: press Next and ▶ Play for each part.
3. Press Next to the Movie step and press ▶ Play.

The video says:

• Two stacks of the same 12 coins.
• Push one stack into a slant. Every slice is the same size at every height.
• So the volumes are equal. That is Cavalieri's principle.

Students open the same lesson on their own device (or work with the board). Press Next to Try it.

Try it together first:

🧱 Build it: the lesson's short 3D build game. Let students play it after Try it. Its score never changes grades.

If time is left, students play the lesson's game steps (they show up between the videos and Check).

Students press Next to Check and answer the 4 questions on their own device. Goal: 100%. 95% or more is Mastered. “Not yet” means try again; students may retry.

Read this question aloud. Students write the answer on a slip of paper with no name or with a class number, and hand it in.

Read this aloud (it is the lesson's hook). Students think, then tell a partner what they notice.

“How much paint does a cylinder-shaped water tower need? Model it with shapes.”

1. Open the lesson link on the board.
2. Press Next to the 🎬 Watch in 3D step and press ▶ Play. Students can drag to turn the model. This lesson has 2 3D videos in a row: press Next and ▶ Play for each part.
3. Press Next to the Movie step and press ▶ Play.

The video says:

• A tree trunk is close to a cylinder: radius 1 foot, height 20 feet.
• Its volume is about pi times 1 squared times 20: about 62.8 cubic feet.
• A model is close, not exact. Real trunks taper, so the true volume is a bit less.

Students open the same lesson on their own device (or work with the board). Press Next to Try it.

Try it together first:

🧱 Build it: the lesson's short 3D build game. Let students play it after Try it. Its score never changes grades.

If time is left, students play the lesson's game steps (they show up between the videos and Check).

Students press Next to Check and answer the 4 questions on their own device. Goal: 100%. 95% or more is Mastered. “Not yet” means try again; students may retry.

Read this question aloud. Students write the answer on a slip of paper with no name or with a class number, and hand it in.