If the sum of the circumferences of two circles with radii R1 and R2 is equal to the circumference of a circle of radius R then
Let three circles be C1, C2 and C
Circumference of circle C = Circumference of circle C1 + Circumference of circle C2
⇒ 2πR = 2πR1 + 2πR2
R = R1 + R2