Let’s solve each problem step by step. The surface area of a rectangular prism is calculated using the formula:
Surface Area = 2 × (length × width + length × height + width × height)
We’ll apply this to each numbered problem.
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1) Dimensions: 9 mm, 5 mm, 13 mm
SA = 2 × (9×5 + 9×13 + 5×13)
= 2 × (45 + 117 + 65)
= 2 × 227
=
454 mm²
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2) Dimensions: 20 cm, 4 cm, 6 cm
SA = 2 × (20×4 + 20×6 + 4×6)
= 2 × (80 + 120 + 24)
= 2 × 224
=
448 cm²
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3) Dimensions: 8 m, 5 m, 14 m
SA = 2 × (8×5 + 8×14 + 5×14)
= 2 × (40 + 112 + 70)
= 2 × 222
=
444 m²
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4) Dimensions: 17 ft, 4 ft, 14 ft
SA = 2 × (17×4 + 17×14 + 4×14)
= 2 × (68 + 238 + 56)
= 2 × 362
=
724 ft²
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5) Dimensions: 13 in, 4 in, 9 in
SA = 2 × (13×4 + 13×9 + 4×9)
= 2 × (52 + 117 + 36)
= 2 × 205
=
410 in²
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6) Dimensions: 14 mm, 7 mm, 9 mm
SA = 2 × (14×7 + 14×9 + 7×9)
= 2 × (98 + 126 + 63)
= 2 × 287
=
574 mm²
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7) Dimensions: 12 cm, 7 cm, 7 cm
SA = 2 × (12×7 + 12×7 + 7×7)
= 2 × (84 + 84 + 49)
= 2 × 217
=
434 cm²
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8) Dimensions: 6 in, 4 in, 12 in
SA = 2 × (6×4 + 6×12 + 4×12)
= 2 × (24 + 72 + 48)
= 2 × 144
=
288 in²
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9) Dimensions: 8 ft, 4 ft, 15 ft
SA = 2 × (8×4 + 8×15 + 4×15)
= 2 × (32 + 120 + 60)
= 2 × 212
=
424 ft²
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10) Gift box: 20 cm long, 14 cm wide, 10 cm high
SA = 2 × (20×14 + 20×10 + 14×10)
= 2 × (280 + 200 + 140)
= 2 × 620
=
1240 cm²
This is how much paper you need to wrap the gift box.
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Final Answer:
1) 454 mm²
2) 448 cm²
3) 444 m²
4) 724 ft²
5) 410 in²
6) 574 mm²
7) 434 cm²
8) 288 in²
9) 424 ft²
10) 1240 cm²
Parent Tip: Review the logic above to help your child master the concept of finding surface area worksheet.
