Question

The sum of circumferences of two circles is $132cm.$ If the radius of one circle is $14cm,$ find the radius of the second circle.

Answer 1

$132=2\pi r_1+2\pi r_2$

$\Rightarrow \frac{132}{2\pi }=r_1+r_2$

$\Rightarrow \frac{132\times 7}{2\times 22}=14+r_2$

$\Rightarrow 21=14+r_2$

$\Rightarrow 7=r_2$

So $r_2=7cm$