Question

What is the circumference of this circle? Use π ≈ 3.14. Round your answer to the nearest tenth of a centimeter

Answer 1

The formula of the circumference of a circle is:

C = 2 * π * r

Since r is not given, I will use all choices to find the radius. Whatever circumference corresponds to the correct radius of the problem, then it is the correct one.

a) 22.0 cm = 2 * 3.14 * r ⇒ r = 22.0 cm / 6.28 ⇒ r =   3.50 cm
b) 69.1 cm = 2 * 3.14 * r ⇒ r = 69.1 cm / 6.28 ⇒ r = 11.00 cm
c) 34.5 cm = 2 * 3.14 * r ⇒ r = 34.5 cm / 6.28 ⇒ r =   5.49 cm
d) 17.3 cm = 2 * 3.14 * r ⇒ r = 17.3 cm / 6.28 ⇒ r =   2.75 cm