Question

Choose the correct alternative answer.

Find the circumference of a circle whose area is 1386 cm²? 

(A) 132 cm²

(B) 132 cm 

(C) 42 cm 

(D) 21 cm²

Answer 1

(B) 132 cm

Area of the circle = πr²

1386 = (22/7) x r² 

r² = 1386 x (7/22) 

= 63 x 7 = 441 

r = √441 … [Taking square root of both sides] 

= 21 cm 

Circumference of the circle = 2πr 

= 2 x (22/7) x 21 

= 132 cm