# How do you find the circumference and the area of a circle with diameter 6m?

Sep 28, 2015

Area of circle = $\pi {r}^{2}$ or $\pi {\left(\frac{d}{2}\right)}^{2}$
Circumference of circle = $\pi d$
For a circle with diameter $6$m this becomes $A \cong 28.27 {m}^{2}$ and $C \cong 18.85 m$

#### Explanation:

The constant $\pi \cong 3.14159$ is the ratio of the circumference of a circle to its diameter (or equivalently to twice it's radius).

$C = \pi d = \pi 2 r$

That same value, $\pi$, is also the ratio of the the area of a circle to the square of its radius

$A = \pi {r}^{2}$

Plugging the given diameter (or diameter divided by 2 for the radius) into these equations gives the required results.