Answer:
Explanation:
Given that a line segment BK is an angle bisector of triangle ABC.
When the line KM intersects BC such that BM=MK
we find an isosceles triangle BMK with two sides equal
Hence by isosceles triangles theorem, two angles opposite equal sides would be equal
i.e.

The isosceles triangle theorem states that If two sides of a triangle are congruent, then angles opposite those sides are congruent.