If the diameter of a circle is increases by 15%, then what will be the percentage increase in its area?

35.75% 30.3% 25% 32.25%

32.25%

15% = \(\frac{3}{20}\) Diameter        20     :      23 Radius            20     :      23 Area              202    :      232                     400     :     529      ⇒ 129 (diff.) Percentage change in area = \(\frac{129}{400}\) × 100 = 32.25%