The radius of a circle whose circumference is equal to the sum of the circumferences of the two circles of diameters 36 cm and 20 cm is


Diameter of first circle = d1 = 36 cm


Diameter of second circle = d2 = 20 cm


Circumference of first circle = πd1 = 36π cm


Circumference of second circle = πd2 = 20π cm


Now, we are given that,


Circumference of circle = Circumference of first circle + Circumference of second circle


πD = πd1 + πd2


πD = 36π + 20π


πD = 56π


D = 56


Radius = 56/2 = 28 cm

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