Question

Find the measure of d.

Answer 1

50°

Explanation:

Recall that an inscribed angle is half the arc length. Since Angle A measures 50°, this means that the arc length of BC (the intercepted arc) is 100°.

Arc BC is also representative of Angle D. In other words, the measure of angle D is half of 100°.

Angle D = 50°.

Answer 2

d = 50°

Explanation:

Inside a circle we can have inscribed angles (angles with the three points on the circle). These angles are half the length of the arc they inscribe.

The arc BC is inscribed by the angle of 50°, so we have:

`50 = mBC/2`

`mBC = 100\°`

The angle d inscribes the arc BC, so we have:

`d = mBC/2`

`d = 100/2`

`d = 50\°`