Question

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

Answer 1

Let the radius of the required circle be r.

Now, Circumference of the required circle = Circumference of circle having radius 19 cm + Circumference of circle having radius 9 cm

⇒ 2πr = 2π × 19 + 2π × 9

⇒ r = 19 + 9

⇒ r = 28 cm

Hence, the radius of the required circle is 28 cm.