Question

The diagram shows a circle with centre O and radius 2.5cm.

A, B & C lie on the circumference of this circle.
Given that AC is a diameter of the circle and AB = 4cm, work out the length of BC

Answer 1

3cm.

Explanation:

As you know, a diameter is the same as twice a radius.

AO= OC.

OC= 2.5cm.

therefore, AC= OA+OC

AC= 2.5+2.5

AC= 5cm.

AB= 4cm.

Using Pythagorean theorem.

BC= √(AC²-AB²).

BC= √(5²-4²)

BC= √(25-16)

BC= √9

BC= 3cm.