In a circle with centre O, a 6 cm long chord is at a  distance 4 cm from the centre. Find the length of the diameter.

14 cm 7 cm 5 cm 10 cm

10 cm

We know that, Pythagoras theorem:  h2 = b2 + p2 r2 = 42 + 32 r = 5 The diameter of the circle  = 2 × 5 = 10 cm