Question

The area of a circle is 4π in². What is the circumference, in inches? Express your answer in terms of π.

Answer 1

4π in

Explanation:

The formula for area is πr². We will work backwards from 4π. First, I will do √4 so I can find r.

√4 = 2

Now, I know that r = 2. Next, I will substitute r into the circumference formula which is 2πr.

2π(2) - I know r is 2 from my previous set.

Now, I will simplify.

2 · 2 π = 4π

Since the question is asking in terms of π, I will not simplify all the way, and leave pi as is.

Answer 2

C = 4π in

Explanation:

We require to find the radius r of the circle

Given the area is 4π , then

πr² = 4π ( divide both sides by π )

r² = 4 ( take the square root of both sides )

r =
`√(4)` = 2

Then

C = 2πr = 2π × 2 = 4π inches