Question 303185
This is an isosceles triangle.

The line containing the bisector of the vertex angle of an isosceles triangle
is a symmetry line for the triangle. 

In an isosceles triangle, the bisector of the vertex angle,
the perpendicular bisector of the base, and the median to the base determine the same line. 

If a triangle has two congruent sides, then the angles opposite them are congruent.