Get Ready · Lesson 10-4: Surface Area of Prisms

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Why this matters for Lesson 10-4: Surface area of a prism means finding the area of every face and adding them up. Opposite faces match, so you often double an area. This runs on area of a rectangle, doubling, and adding several areas. Warm those up first.

Quick Check · 1 minute

Where should you start?

Answer these 3, then press Show my path. No grade — this just points you to the right level.

1. Area of a rectangle 7 long and 2 wide?

2. Double an area of 15. What is 2 × 15?

3. On a box, the top face and the bottom face are…

🧱 Start at Level 0. We'll build this from the ground up with small steps. That's totally fine — take your time below.

🛠️ Start at Level 1. You've got the idea — a little guided practice and you'll be ready.

🚀 Start at Level 2. Your basics are strong! Do the quick warm-up and head into the lesson.

⚠️ Answer all 3 questions first, then press Show my path.

Learn It

Match the faces, then add

A box has 3 pairs of matching faces: top/bottom, front/back, left/right. Find the area of one face in each pair, double it, then add all three doubled areas. Answer is in square units.

Double a face: if a face is 4 × 3 = 12, the matching pair is 2 × 12 = 24.

Add the pairs: if the three doubled pairs are 24, 16, and 12, total surface area = 24 + 16 + 12 = 52 square units.

Practice · Your Level

Try It

Your quick check picks one for you, but you can switch any time:

Level 0 Find a face area, then double it.

A. Area of a 4 × 2 face = ___

Hint

4 × 2 = 8.

B. Double it for the matching pair: 2 × 8 = ___

Hint

2 × 8 = 16.

C. Now add another pair: 16 + 6 = ___

Hint

16 + 6 = 22.

Level 1 Double faces and add the pairs.

A. A face is 5 × 3. Doubled pair = 2 × (5 × 3) = ___

Hint

5 × 3 = 15, then 2 × 15 = 30.

B. Three pairs of faces total 20, 12, and 6. Add them: ___

Hint

20 + 12 = 32, then 32 + 6 = 38.

C. How many matching pairs of faces does a box have?

Hint

Top/bottom, front/back, left/right = 3 pairs.

Level 2 Stretch: full surface area from three pairs.

A. Faces are 6×2, 6×3, and 2×3. Pairs are 2×12, 2×18, 2×6. What is the total surface area?

Hint

12+18+6 = 36, then doubled: 2 × 36 = 72.

B. A face is 5 × 4. What is the total area of that matching pair? (square units)

Hint

5 × 4 = 20, then 2 × 20 = 40.

★

Exit Ticket

Show You're Ready

1. A face is 4 × 5. What is the doubled pair (2 × area)?

Hint

4 × 5 = 20, then 2 × 20 = 40.

2. Add three pairs of faces: 18 + 12 + 10 = ___

Hint

18 + 12 = 30, then 30 + 10 = 40 square units.

🎉 You're warmed up!

You've practiced exactly what Lesson 10-4 uses. Time to dive in.

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