QQuestion
If the length of the radius of a sphere is increased by 50%, find how much percent will be increased of its curved surface area.
✓Answer
Original radius = r (let)
New radius = 1.5 r
Original Surface Area = 4πr²
New Surface Area = 4π(1.5r)² = 9πr²
Increase % = \text{9πr² − 4πr²}\over \text{4πr²} × 100% = = \text{5πr²}\over \text{4πr²} × 100% = 125%
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