Question

Find the area and the circumference of a circle with radius 3km.Write your answers in terms of π, and be sure to include the correct units in your answers.

Answer 1

To find:

a) Area of the circle.

b) Circumference of the circle.

Solution:

a) It is known that the area of a circle is whose radius is r is given by:

`Area=\pi r^2`

So, the area of the given circle is :

`\begin{gathered} A=\pi(3)^2 \\ =9\pi km^2 \end{gathered}`

b)

It is known that the circumference of a circle whose radius is r is given by:

`C=2\pi r`

So, the area of the given circle is :

`\begin{gathered} C=2\pi(3) \\ =6\pi km \end{gathered}`