Question

find the diameter of circle whose perimeter is 132cm

Answer 1

Perimeter=132cm

Perimeter=2πr
132=2×22/7 ×r
132=44/7 ×r
132×7 /44 =r
21=r
r=21
Diameter=2×radius
Diameter=2×21
Diameter=42cm.

Answer 2

circumference
$2\pi \: r$

2 ×22/7 ×r =132
44r = 132 ×7
r =924/44
r=21