If the radius of a circle decreased by 50% its area is decreased by:	Choose the correct choice from the following.
A) 75 B) 79 C) 72 D) 70 E) 80
Original area = πr(power)2   New area = π(r/2)(power)2 = (πr(power)2)/4   Reduction in area = [(πr(power)2 - (πr(power)2)/4]2 = (3πr(power)2)/4   Reduction percent = ((3πr(power)2)/4 × 1/(πr(power)2 × 100) % = 75%   75nswer is 75.
<result>A</result>
If the radius of a circle decreased by 50% its area is decreased by: