# Find the area and the circumference of a circle with radius 5yd?

Apr 14, 2018

C: $10 \pi$ yards
A: $25 \pi$ yards squared

#### Explanation:

Circumference: $2 \pi r$ or $\mathrm{dp} i$ (where $r$ is the radius and $d$ is the diameter, which is twice the length of the radius)

Area: $\pi {r}^{2}$

Circumference: $2 \cdot \pi \cdot 5 = 10 \pi$ yards (if you're using an approximation like $3.14$ for $\pi$, multiply that by $10$)

Area: ${5}^{2} \pi = 25 \pi$ yards squared (if you're using an approximation like $3.14$ for $\pi$, multiply that by $25$)

Apr 14, 2018

The circumference is $31.4$ $\text{yd}$, and the area is $78.5$ ${\text{yd}}^{2}$

#### Explanation:

There are special formulas to find the circumference and area of a circle.

Circumference:
$C = 2 \pi r$

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

• $r$ is the $\text{radius}$
• $\pi$ is approximately $3.14$ They've given you the radius of the circle, so all you have to do is plug it into the equation:

Circumference:
$C = 2 \pi r$

$C = 2 \left(3.14\right) \left(5\right)$

$C = 31.4$ $\text{yd}$.

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

$A = \left(3.14\right) \left({5}^{2}\right)$

$A = 3.14 \left(25\right)$

$A = 78.5$ ${\text{yd}}^{2}$

So the circumference is $31.4$ $\text{yd}$, and the area is $78.5$ ${\text{yd}}^{2}$.