Find the area of a circle whose circumference is 22 cm.
Let r be the radius of the circle, then circumference = 2πr
⇒ 2πr = 22 cm
⇒ r = 22/2π = 22 × 7/2 × 22 = 7/2 cm
∴ Area of circle = πr^{2}
= 22/7 × 7/2 × 7/2 cm^{2} = 77/2 cm^{2}
= 38.5 cm^{2 }