Question

What is the radius of a circle with an area of 78.5 cubic inches? Use 3.14 for pi. Enter your answer in the box.

Answer 1

Answer:

5 inches

Step-by-step explanation:

Given : A circle with an area of 78.5 cubic inches .

To Find: What is the radius of a circle with an area of 78.5 cubic inches?

Solution :

Formula of area of circle:

$\pi r^{2}$

where r is the Radius of circle

Since we are given thet the area of circle 78.5 cubic inches

Using the above formula :

$78.5=\pi r^{2}$

Using π =3.14

$78.5=3.14*r^{2}$

$\frac{78.5}{3.14} =r^{2}$

$25=r^{2}$

$\sqrt{25} =r$

$r=5$

Thus , 5 inches is the radius of a circle with an area of 78.5 cubic inches

Answer 2

$\bf \textit{area of a circle}\\\\ A=\pi r^2~~ \begin{cases} r=radius\\[-0.5em] \hrulefill\\ A=78.5 \end{cases}\implies 78.5=\pi r^2\implies \cfrac{78.5}{\pi }=r^2 \\\\\\ \sqrt{\cfrac{78.5}{\pi }}=r\implies 4.9987\approx r$