Answer:
<ACB = 20°
Step-by-step explanation:
Given:
Measure of angle AOB = 40°
The measure of angle ACB = ½AOB
This could be explained as the angle at the circumference of a circle equals ½ the angle at the centre of the circle because they can be said to be on the same arc.
Here the angle at the circumference, <ACB is ½ half the angle at the centre of the circle, <AOB.
It can be expressed as:
<ACB = ½<AOB
Where,
<AOB = 40°
<ACB = ½ * 40°
<ACB = 20°
Measure of angle ACB = 20°
The diagram is attached
