The chord of the circle and its distance from the centre of the circle will be as shown in the figure above. M is the midpoint of the chord. BC is the radius of the circle.

Consider Rt Triangle BMC. Using Pythagoras theorem, we will have

BC² = CM² + BM²

=3² + 4²

= 25

Thus BC=5ft. Diameter of the circle will be 10ft.

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