Question

In this figure, what fraction of the circumference of the circle is the length of the arc ADB?

Answer 1

Construction: Join points A and B with centre O of the circle.

Given: ∠ACB = 60°

We know that angle made by an arc at any point on the alternate arc is equal to half the angle made at the centre.

We know that measure of an arc is equal to the measure of the corresponding central angle.

⇒ m (arc ADB) = ∠AOB

⇒ m (arc ADB) = 120°

Now,

Thus, the length of the arc ADB is of the circumference of the circle.