B triangle ABC angle is 80 degrees angle C is equal to 55 degrees

B triangle ABC angle is 80 degrees angle C is equal to 55 degrees prove that the bessictrix AM angle BAD of a triangle adjacent to angle A is parallel to BC.

Since the angle BAD is adjacent to the angle BAC, the value of the angle BAD = 180 – BAC = 180 – 80 = 100.

AM, by condition, is the bisector of the angle BAD, then the angle BAM = MAD = BAD / 2 = 100/2 = 50.

Angle MAD = BCA = 50.

Since the straight lines AM and BC intersect the straight line CD at the same angle, the straight line AM is parallel to BC, which was required to be proved.