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The total surface area of a hemisphere is 4158 cm2. Find its diameter (in cm).
- A21
- B84
- C42
- D63
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CCommunity
Formula for Total surface area of a hemisphere = 3πR2 (where R is the radius)
⇒ 3 × (22/7) × R2 = 4158
⇒ R2 = 4158 × (7/22) × (1/3)
⇒ R2 = 4158 × (7/22) × (1/3)
⇒ R2 = 441
⇒ R = √441 = 21
Diameter = 2R = 2 × 21 = 42
∴ Required Diameter = 42
⇒ 3 × (22/7) × R2 = 4158
⇒ R2 = 4158 × (7/22) × (1/3)
⇒ R2 = 4158 × (7/22) × (1/3)
⇒ R2 = 441
⇒ R = √441 = 21
Diameter = 2R = 2 × 21 = 42
∴ Required Diameter = 42