# Math Help - What is the circumference of a circle with a radius of 4.2 inches?

1. ## What is the circumference of a circle with a radius of 4.2 inches?

What is the circumference of a circle with a radius of 4.2 inches?

A) 13.2 in.
B) 6.6 in.
C) 8.4 in.
D) 55.4 in.
E) 26.4 in.

2. Originally Posted by Leo34005
What is the circumference of a circle with a radius of 4.2 inches?

A) 13.2 in.
B) 6.6 in.
C) 8.4 in.
D) 55.4 in.
E) 26.4 in.
Please show your attempt and state where you get stuck.

NB: I would appreciate that no other replies be given until the OP has done what I asked.

3. C = 2πr

Since the radius = 4.2 inches, r = 4.2. So we have:

C = 2π(4.2)
==> C = 8.4π
==> C ≈ 26.39 in^2

Therefore, the answer is E

4. Originally Posted by Leo34005
C = 2πr

Since the radius = 4.2 inches, r = 4.2. So we have:

C = 2π(4.2)
==> C = 8.4π
==> C ≈ 26.39 in^2

Therefore, the answer is E
Correct (except the unit is inches, not square inches).