Question

The ratio of diameter of two circles is 3:4.Find the ratio of their areas

Answer 1

let the diameter of two circles be 3x and 4x
$\frac{area \: of \: 1st \: circle}{area \: of \: 2nd \: circle} = \frac{\pi {( \frac{3x}{2} )}^{2} }{\pi{( \frac{4x}{2} )}^{2} } = \frac{9}{16}$
required ratio=9:16