Question

Find the area of a circle whose circumference is 22 cm.

Answer 1

Let r be the radius of the circle, then circumference = 2πr
⇒ 2πr = 22 cm
⇒ r = `22/(2π) = (22 xx 7)/(2 xx 22) = 7/2 "cm"` 

∴ Area of circle = πr² 
∴ Area of circle = `22/7 xx 7/2 xx 7/2 "cm"^2 = 77/2 "cm"^2`
∴ Area of circle = 38.5 cm².