Question

Find the circumference of a circle when the area of the circle is 64πcm²​

Answer 1

`\textit{area of a circle}\\\\ A=\pi r^2 ~~ \begin{cases} r=radius\\[-0.5em] \hrulefill\\ A=64\pi \end{cases}\implies 64\pi =\pi r^2 \\\\\\ \cfrac{64\pi }{\pi }=r^2\implies 64=r^2\implies √(64)=r\implies 8=r \\\\[-0.35em] ~\dotfill\\\\ \textit{circumference of a circle}\\\\ C=2\pi r ~~ \begin{cases} r=radius\\[-0.5em] \hrulefill\\ r=8 \end{cases}\implies C=2\pi (8)\implies C=16\pi \implies C\approx 50.27~cm`

Answer 2

50.24 cm

Explanation:

We Know

The area of the circle = r² · π

Area of circle = 64π cm²

r² · π = 64π

r² = 64

r = 8 cm

Circumference of circle = 2 · r · π

We Take

2 · 8 · 3.14 = 50.24 cm

So, the circumference of the circle is 50.24 cm.