Question

Find the circumference and the area of a circle with radius 5 km.Write your answers in terms of 1, and be sure to include the correct units in your answers.

Answer 1

Given:

Radius = 5 km.

circumference of the circle

`\text{circumference =}2\pi r`

Substitute r=5 in the formula, we get

`\text{circumference =}2\pi*5`

`\text{circumference =}10\pi km`

The area of the circle is

`\text{Area =}\pi r^2`

Substitute r=5 in the formula, we get

`\text{Area =}\pi(5)^2`

`\text{Area =}25\pi km^2`

Hence the answers are

`\text{circumference =}10\pi km`

`\text{Area =}25\pi km^2`