The sum of the diameters of the two circles is 10 cm. If the radius of one circle is RCM, the perimeter of the other circle is? Cm

The sum of the diameters of the two circles is 10 cm. If the radius of one circle is RCM, the perimeter of the other circle is? Cm

Let 2m + 2R = 10, where m is the radius of a circle and R is known
It is concluded that M = 5-r
So the circumference of the other circle is 2 Π (5-r)