Let’s solve each problem step by step. We’ll use the formulas for surface area and volume of a sphere:
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Surface Area (SA) = 4πr²
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Volume (V) = (4/3)πr³
We’ll round answers to the nearest hundredth if needed, as instructed.
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Problem 1: Radius = 11 ft
SA = 4 × π × (11)² = 4 × π × 121 = 484π ≈ 484 × 3.1416 ≈
1520.53 ft²
V = (4/3) × π × (11)³ = (4/3) × π × 1331 = (5324/3)π ≈ 1774.6667 × 3.1416 ≈
5575.28 ft³
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Problem 2: Radius = 6 in
SA = 4 × π × 36 = 144π ≈ 144 × 3.1416 ≈
452.39 in²
V = (4/3) × π × 216 = 288π ≈ 288 × 3.1416 ≈
904.78 in³
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Problem 3: Radius = 13 in
SA = 4 × π × 169 = 676π ≈ 676 × 3.1416 ≈
2123.72 in²
V = (4/3) × π × 2197 = (8788/3)π ≈ 2929.333 × 3.1416 ≈
9202.77 in³
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Problem 4: Radius = 2 cm
SA = 4 × π × 4 = 16π ≈ 16 × 3.1416 ≈
50.27 cm²
V = (4/3) × π × 8 = (32/3)π ≈ 10.6667 × 3.1416 ≈
33.51 cm³
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Problem 5: Radius = 5 mm
SA = 4 × π × 25 = 100π ≈ 100 × 3.1416 ≈
314.16 mm²
V = (4/3) × π × 125 = (500/3)π ≈ 166.6667 × 3.1416 ≈
523.60 mm³
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Problem 6: Radius = 8 mm
SA = 4 × π × 64 = 256π ≈ 256 × 3.1416 ≈
804.25 mm²
V = (4/3) × π × 512 = (2048/3)π ≈ 682.6667 × 3.1416 ≈
2144.66 mm³
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Problem 7: Radius = 2 ft
Same as Problem 4 but in feet.
SA = 4 × π × 4 = 16π ≈
50.27 ft²
V = (4/3) × π × 8 = (32/3)π ≈
33.51 ft³
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Problem 8: Radius = 14 yd
SA = 4 × π × 196 = 784π ≈ 784 × 3.1416 ≈
2463.01 yd²
V = (4/3) × π × 2744 = (10976/3)π ≈ 3658.6667 × 3.1416 ≈
11494.04 yd³
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Problem 9: Radius = 9 cm
SA = 4 × π × 81 = 324π ≈ 324 × 3.1416 ≈
1017.88 cm²
V = (4/3) × π × 729 = 972π ≈ 972 × 3.1416 ≈
3053.63 cm³
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Final Answer:
1) Surface Area: 1520.53 ft², Volume: 5575.28 ft³
2) Surface Area: 452.39 in², Volume: 904.78 in³
3) Surface Area: 2123.72 in², Volume: 9202.77 in³
4) Surface Area: 50.27 cm², Volume: 33.51 cm³
5) Surface Area: 314.16 mm², Volume: 523.60 mm³
6) Surface Area: 804.25 mm², Volume: 2144.66 mm³
7) Surface Area: 50.27 ft², Volume: 33.51 ft³
8) Surface Area: 2463.01 yd², Volume: 11494.04 yd³
9) Surface Area: 1017.88 cm², Volume: 3053.63 cm³
Parent Tip: Review the logic above to help your child master the concept of volume worksheet grade 8.