Question

A small pizza has a diameter of 21 cm.

Answer 1

Circumference = pi * diameter = 3.14 * 21 cm = 65.94 cm. So the answer is 65.94 cm and this is correct

Answer 2

The circumference of any circle is (pi) x (the diameter of the circle).

The problem gives you both numbers, so all you have to do is multiply them.

Circumference = (pi) x (diameter) = (3.14) x (21cm) = 65.94 cm .