Question

Find the length of the chord of a circle in the following when: 

Radius is 13 cm and the distance from the centre is 12 cm 

Answer 1

AC = CB ----(1)    (Perpendicular from centre to a chord bisects the chord) 

In right t. ACO, 

By Pythagoras theorem, OA² = OC² + AC² 

13² -12² = AC² 

AC² = 169 - 144 = 25 

AC = 5 cm 

∴ length of chord AB = 2AC     (from (1))