Question

The perimeter of a circle is 4πr cm. What is the area of the circle?

Answer 1

We have :
Given perimeter of the circle = 4$\mathrm{\pi }$r cm = 2​$\mathrm{\pi }$ (2r) cm

We know that, the perimeter of a circle = 2$\mathrm{\pi }$r

∴ Radius of the circle = 2r cm

Area of the circle= $\mathrm{\pi }$r² = ​$\mathrm{\pi }$ (2r)² = 4​$\mathrm{\pi }$r^{2 .}