Question

What is the radius of a circle with an area of 78.5 cubic inches? use 3.14 for pie

Answer 1

radius = 5 in

Explanation:

Using the formula for calculating the area (A) of a circle

A = πr² ( r is the radius )

here A = 78.5, hence

3.14r² = 78.5 ( divide both sides by 3.14 )

r² =
`(78.5)/(3.14)` = 25 ( take the square root of both sides )

r =
`√(25)` = 5

Answer 2

The radius is 5 in

Explanation:

The area of a circle is given by the formula

A = pi *r^2

We know the area = 78.5 in^2 (volume would be in^3 area is in^2)

78.5 = 3.14*r^2

Divide each side by 3.14

78.5/3.14 = 3.14/3.14*r^2

25 = r^2

Take the square root of each side

sqrt(25) sqrt(r^2)

5 =r