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The area of a semicircle is 308 cm2. Calculate its perimeter (in cm).
- A144
- B49
- C98
- D72
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CCommunity
Formula for Area of a semicircle = πr2/2
Given πr2/2 = 308
⇒ (22/7) × r2 = 308 × 2
⇒ r2 = 308 × 2 × (7/22) = 14 × 14
⇒ r = √(14 × 14) = 14 cm
Diameter (d) = 2 × 14 = 28 cm
Perimeter of semicircle = [(1/2) πd] + d = [(1/2) × (22/7) × 28] + 28 = 44 + 28 = 72
∴ Required Perimeter = 72 cm
Given πr2/2 = 308
⇒ (22/7) × r2 = 308 × 2
⇒ r2 = 308 × 2 × (7/22) = 14 × 14
⇒ r = √(14 × 14) = 14 cm
Diameter (d) = 2 × 14 = 28 cm
Perimeter of semicircle = [(1/2) πd] + d = [(1/2) × (22/7) × 28] + 28 = 44 + 28 = 72
∴ Required Perimeter = 72 cm