Question

Rewrite the formula for area of a circle to find the radius of a circle.

The area of a circle (A) is given by the formula A=πr^2 where r is the circle's radius. The formula to find r is (1)_____. If A=54 centimeters^2 and π=22/7, r is (2)_____ centimeters.

1. (A/pi)^1/2; A^2/pi; pi/A

2. 4.15; 2.33; 17.2

Answer 1

The correct answers are: Part A. A/π^1/2 = r and Part B. 4.15 centimeters.

Explanation:

1. Let's review all the information provided for solving this question:

Area of the circle = π*r² where r is the circle's radius

2. Let's find the solution for r for part A and for part B:

Part A:

A = π*r²

A/π = r²

√A/π = r

A/π^1/2 = r

Part B:

If A = 54 centimeters² and π = 22/7, what is the value of r in centimeters?

Using the result of part A and replacing with the real values, we have:

√A/π = r

√54/(22/7) = r

√54 * 7/22 = r

√378/22 = r

√17.1818 = r

4.1451 = r

4.15 = r (Rounding to two decimal places)