The sum of the radii of two circles is 140cm and the difference of their circumferences is 88cm. Find the diameters of the circles.
Let radius of first circle = r1cm
Let radius of second circle = r2cm
So,
r1 + r2 = 140cm …. (i)
2πr1 – 2πr2 = 88cm
r1 - r2 = 14cm …. (ii)
By adding equation 1 & 2
r1 = 77cm
From equation 1
77 + r1 = 140 cm
r2 = 140 – 77 = 63cm
r2 = 63cm
So,
Diameter of first circle = 2×r1 = 2×77 = 154cm
Diameter of second circle = 2×r2 = 2×63 = 126cm