Question

A chord of length 16 cm is at a distance of 6 cm from the centre of a circle. Find the radius of the circle.

Solution

1. The perpendicular from the centre to a chord bisects the chord, so half the chord is 16 / 2 = 8 cm.
2. The radius is the hypotenuse of a right triangle with sides 8 cm and 6 cm.
3. radius^2 = 8^2 + 6^2 = 64 + 36 = 100.
4. Radius = √100 = 10 cm.