5.7 · Part II
Application Practice for Today's Problem
Surface Area of Prisms · Surface area
- Calculate area of Top & Bottom: 2 × (l · w)
- Calculate area of Front & Back: 2 × (l · h)
- Calculate area of Left & Right: 2 × (w · h), then sum all three pairs
- Surface Area of Prisms (Área de superficie de prismas) — The total area of all bases and lateral faces of a prism. Formula: SA = 2B + lateral area.
- Surface area (Área de superficie) — The total area of all the flat sides of a solid.
- Rectangular prism (Prisma rectangular) — A solid box shape with six flat rectangle sides.
- Triangular prism (Prisma triangular) — A solid with two triangle ends and three flat rectangle sides.
- Face (Cara) — One flat side of a solid shape.
- Net (Plantilla (desarrollo plano)) — A flat shape that folds up into a solid.
- A common mistake in Surface Area of Prisms is confusing surface area with volume — multiplying l × w × h (which finds the space INSIDE the prism, in cubic units) instead of adding the areas of all the faces (SA = 2lw + 2lh + 2wh, in square units). A second common slip is forgetting to double one face pair, like writing 2(l×w) + 2(l×h) + (w×h) instead of + 2(w×h) — always count all 6 faces (or all 5 for a triangular prism) before you submit.
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1 MULTIPLE CHOICE
A triangular prism has triangular bases with base 6 in and height 4 in. The prism is 10 in long and the two slant sides of the triangle are each 5 in. What is the surface area?
- A184 in²
- B160 in²
- C124 in²
- D184 in³
FormulaPut the numbers inWork it outAnswer with its unit- 1Name itWhich measure is asked?
- 2Write the formulaBefore any numbers.
- 3SubstituteMatch each letter.
- 4Unitunits, sq units, or cubic?
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2 MULTIPLE CHOICE
A rectangular time capsule box measures 3 in by 4 in by 5 in. How much wrapping paper covers its surface (no overlap)?
- A94 in²
- B60 in²
- C47 in²
- D94 in³
✏️ Workspace & Solution Steps -
3 MULTIPLE CHOICE
A rectangular capsule crate is 6 cm long, 5 cm wide, and 4 cm tall. How much cardboard is needed to cover all its faces?
- A148 cm²
- B120 cm²
- C74 cm²
- D148 cm³
✏️ Workspace & Solution Steps -
4 MULTIPLE CHOICE
A triangular prism is 10 in long. Its triangle ends have base 8 in, height 6 in, and sides 8, 6, and 10 in. Find its surface area.
- A288 in²
- B240 in²
- C48 in²
- D288 in³
FormulaPut the numbers inWork it outAnswer with its unit- 1Name itWhich measure is asked?
- 2Write the formulaBefore any numbers.
- 3SubstituteMatch each letter.
- 4Unitunits, sq units, or cubic?
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5 OPEN RESPONSE
A company ships products in two container options: a rectangular prism (8 × 6 × 4 in) or a triangular prism (triangle base 8 in, triangle height 6 in, prism length 8 in, slant sides 6.3 in each). Both must be wrapped in protective film. Which shape uses LESS film? Show your work.
💬 Sentence Starter: Rectangular prism SA = 2(___) + 2(___) + 2(___) = ___ in². Triangular prism SA = 2(___) + ___ + ___ + ___ = ___ in². The ___ uses less film because ___.✏️ Mathematical Justification & Response
Writing Task: Justify why your mathematical solution is accurate and complete.