Question

The diameter of a circle is 4 cm. Which equation can be used to find its circumference

A: C = pi x 44
B: C = pi x 2
C: C = 16 x pi
D: C = pi x 4

Answer 1

D: C = 4π

Explanation:

The formula for circumference is C = 2πr

The diameter is 4 which means the radius is 2.

Plug the value of r into the formula.

C = 2π2

C = 4π

D: C = 4π