Question

find the diameter of a circle whose circumference is 132cm

Answer 1

c= 2πr
132 = 2×22/7×r
132×7/22×2= r
r= 21
d= 2r = 2×21
= 42cm

Answer 2

$2\pi \: r = 132 \\ r = 132 \div \frac{7}{44} = 21$