Javier wants to prove that the base angles of an isosceles triangle are congruent. To do this, he draws triangle ABC,
with AB = BC. He will then prove that ZA and C are congruent by dividing triangle ABC into two triangles and
using triangle congruence.
Which of the following must be part of Javier's proof?
drawing a line parallel to AC through the midpoints of AB and BC
drawing a line parallel to BC through the midpoints of AB and AC
drawing a line perpendicular to AC through point B
drawing a line perpendicular to BC through point A