Question

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

Radius is 6.5 cm and the distance from the centre is 2.5 cm 

Answer 1

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

In right  Δ OAB, 

By Pythagoras theorem, OB² = OA² + AB² 

AB² = 6.5² + 2.5²

= 42.25 - 6.25 = 36 

AB = 6cm 

∴ Length of chord BC = 2 AB   (from (1))

= 2 (6) = 12 cm