Question

If the bisector of the exterior vertical
base,
angle of a triangle is parallel to the base.
show that the triangle is isosceles.​

Answer 1

Answer:

Join A to D

Hence,

AD∥BC

⇒∠ACB=∠CAD(alternateangle)

⇒and∠BAC=∠ACD(alternateangle)

⇒

Hence

AB=AC (by ASA congurency )

so, it is isosceles triangle.