Let’s solve each problem step by step.
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1a. Find the surface area of this rectangular prism.
Dimensions: length = 7, width = 3, height = 5
Surface Area formula for a rectangular prism:
SA = 2(lw + lh + wh)
Plug in the numbers:
lw = 7 × 3 = 21
lh = 7 × 5 = 35
wh = 3 × 5 = 15
Add them: 21 + 35 + 15 = 71
Multiply by 2: 71 × 2 =
142
✔ Surface Area = 142 square units
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1b. Find the volume of this rectangular prism.
Dimensions: length = 7, width = 5, height = 8
Volume formula: V = l × w × h
V = 7 × 5 × 8
First: 7 × 5 = 35
Then: 35 × 8 = 280
✔ Volume = 280 cubic units
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2a. Find the volume of this rectangular prism.
Dimensions: length = 8, width = 5, height = 7
V = 8 × 5 × 7
8 × 5 = 40
40 × 7 = 280
✔ Volume = 280 cubic units
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2b. Find the surface area of this rectangular prism.
Dimensions: length = 7, width = 2, height = 8
SA = 2(lw + lh + wh)
lw = 7 × 2 = 14
lh = 7 × 8 = 56
wh = 2 × 8 = 16
Add: 14 + 56 + 16 = 86
Multiply by 2: 86 × 2 =
172
✔ Surface Area = 172 square units
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3a. Find the surface area of this rectangular prism.
Dimensions: length = 4, width = 1, height = 8
SA = 2(lw + lh + wh)
lw = 4 × 1 = 4
lh = 4 × 8 = 32
wh = 1 × 8 = 8
Add: 4 + 32 + 8 = 44
Multiply by 2: 44 × 2 =
88
✔ Surface Area = 88 square units
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3b. Find the surface area of this rectangular prism.
Dimensions: length = 5, width = 4, height = 1
SA = 2(lw + lh + wh)
lw = 5 × 4 = 20
lh = 5 × 1 = 5
wh = 4 × 1 = 4
Add: 20 + 5 + 4 = 29
Multiply by 2: 29 × 2 =
58
✔ Surface Area = 58 square units
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Final Answer:
1a. 142
1b. 280
2a. 280
2b. 172
3a. 88
3b. 58
Parent Tip: Review the logic above to help your child master the concept of volume and surface area worksheets grade 7.
