# If the diameter of a circle is 12 inches, what is the area, circumference and the radius?

$R . = 6$, $C . \approx 38$ and $A . \approx 113$.
First you need to find the radius, the key term to find the radius is $\mathrm{di} a m e t e r = 2 \cdot r a \mathrm{di} u s$; therefore the radius $r$ is $\frac{12}{2} = 6$ inches.
To find the area of a circle, you need to use the formula $A = \pi \cdot {r}^{2}$; therefore the area $A$ is $\pi \cdot {6}^{2} \approx 113$ square inches.
To find the circumference of a circle, you will use the formula $C = 2 \cdot \pi \cdot r$; therefore the circumference $C$ is $2 \cdot \pi \cdot 6 \approx 38$ inches.