MathDB
Change in the Area of a Circle

Source:

June 13, 2009
geometry

Problem Statement

The area of a circle is doubled when its radius r r is increased by n n. Then r r equals: (A)\ n(\sqrt{2} \plus{} 1)\qquad (B)\ n(\sqrt{2} \minus{} 1)\qquad (C)\ n\qquad (D)\ n(2 \minus{} \sqrt{2})\qquad (E)\ \frac{n\pi}{\sqrt{2} \plus{} 1}