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

Explanation

Circumference of first circle ` = 2pir_1 = 2pi**19 = 38pi`

Circumference of second circle ` = 2pir_2 = 2pi**9 = 18pi`

Circumference of third circle ` = 18pi+38pi = 56pi`

Let radius of third circle is `R` cm.

Then,
`2piR = 56pi`

`=>R = (56pi)/(2pi) = 28cm`