Question

The ratio between the diameter of two circles is 3:5 find the ratio between thier areas​

Answer 1

The ratio between their areas is 9:25

Answer 2

$\underline{\red{\sf Given :-}}$

• Ratios of diameters of two circles is 3:5

$\underline{\red{\sf To\:Find :-}}$

• Ratio of areas of ∆.

$\underline{\red{\sf Solution :-}}$

Let the given ratio be 3x : 5x.

As we know that area of ∆ is ,

$\boxed{\blue{\bf Area_{circle}=\pi\bigg(\dfrac{d}{2}\bigg)^2}}$

$\sf \implies A_1:A_2=\pi \bigg(\dfrac{3x}{2}\bigg)^2 : \pi \bigg(\dfrac{5x}{2}\bigg)^2\\\\\sf\implies A_1:A_2= \dfrac{9x^2}{4}:\dfrac{25x^2}{4} \\\\\boxed{\green{\sf \leadsto A_1:A_2=9:25 }}$