Geometry

Question Analysis

This question involves the concept of an angle bisector.

Key Concept Explanation

An angle bisector is a ray that divides an angle into two equal - measure angles. So, if a ray bisects an angle, the measure of each of the resulting angles is half of the measure of the original angle.

Step - by - Step Solution

1. Recall the property of an angle bisector. Since  bisects  (which is the same as ), we know that .

2. Given that