Question

The radii of two circles are 19cm and 9cm respectively. Find the radius and area of the circle which has circumferences is equal to sum of circumference of two circles.

Answer 1

Radius of 1^st circle = 19 cm

Radius of 2^nd circle = 9 cm

Circumference of 1^st circle = 2π(19) = 38π cm

Circumference of 2^nd circle = 2π (9) = 18π cm

Let radius of required circle = R cm

Circumference of required circle = 2πR = c₁+c₂

2πR = 38π + 18π

2πR = 56π

R = 28 cms

Area of required circle = πr²

=22/7 x 28 x 28

=2464 cm²