Question

Find the area and the circumstances of a circle with diameter 9ft. Use the value 3.14 for n, and do not round your answers. Be sure to include the correct unit in your answers.

Answer 1

Recall that the area of a circle is given by the following formula:

$A=\pi r^2,$

where r is the radius of the circle. Also, recall that the diameter is two times the radius.

Now, you are given that the circle has a diameter equal to 9ft, therefore, its radius is:

$r=\frac{9ft}{2}=4.5ft.$

Substituting the above value in the formula for the area you get:

$A=\pi(4.5ft)^2=3.14(20.25ft^2)=63.585ft^2.$

The circumference of a circle is given by the following formula:

$C=d\pi,$

where d is the diameter. Therefore, the circumference of the given circle is:

$C=3.14(9ft)=28.26ft.$

Answer:

$\begin{gathered} Area=63.585ft^2, \\ Circumference=28.26ft. \end{gathered}$