Two circles with circumference 44π cm and 20π cm respectively touch internally. Find the distance between their centres.
Let C1 and C2 be the circumferences of the circle with radii ‘r’ and ‘s’ respectively.
C1 = 2πr = 44π
r = 22cm
C2 = 2πs = 20π
s = 10cm
The distance between their centres = r – s
= 22 – 10
= 12cm