If the radius of a circle is decreased by 50%, find the percentage decrease in its area. A) 55% B) 65% C) 75% D) 85%
Let r1 = 100
Then r2 = 50
A1 = π × 1002 = 10000π
A2 = π × 502 = 2500π
Decrease in area = 10000π - 2500π = 7500π
Percentage decrease in area = 7500π×10010000π=75%