Strike a chord

Can you work out the radius of a circle from some information about a chord?
Exploring and noticing Working systematically Conjecturing and generalising Visualising and representing Reasoning, convincing and proving
Being curious Being resourceful Being resilient Being collaborative





Image
Strike a chord
On a circle, there is a chord which has length 8 cm.

The shortest distance from the chord to the centre of the circle is 3 cm.

Find the radius of the circle.

This problem is taken from the World Mathematics Championships