# How do you find the area if diameter is 12 cm?

Sep 20, 2015

I found: $A = 113 c {m}^{2}$

#### Explanation:

Consider that radius $r$ is:
$r = \frac{d}{2} = \frac{12}{2} = 6 c m$
Area $A$ is:
$A = \pi {r}^{2} = 3.14 \cdot 36 = 113 c {m}^{2}$

Sep 20, 2015

$113 c {m}^{2}$

#### Explanation:

I assume you meant "the area of a disk" because you say "diameter" (but it is not so clear from the question, you could have meant the area of a "sphere" (which is in 3D), but I am assuming you are talking about a "disk").

There is a simple formula for the area of a disk:
$A r e a = \pi {r}^{2}$
$A r e a = \pi {\left(6 c m\right)}^{2} = \pi \cdot 36 \left(c {m}^{2}\right)$
$A r e a = 113 c {m}^{2}$