Question

Let and be two lines intersecting at a point O. Let be a ray bisecting ∠BOD. Prove that the extension of to the left of O bisects ∠AOC.

Answer 1

Let the extended line be OY

Here, XY is a straight line

° … (1)

°

… (2)

Subtracting (2) from (1):

Hence, OY is the bisector of angle AOC.