Since AB is the perpendicular bisector of IK, we could know that 1. IJ = JK 2. angle AJI = angle AJK = 90 degrees
We also know that AJ is the common side of both the triangle AJI and AJK. Therefore, we can conclude that the two triangles are congruent (reason: side angle side).
Thus, AI = AK (corresponding sides of congruent triangles).
It can't be isosceles triangle because has at least one line of symmetry and an equilateral triangle has three lines of symmetry... While scalene does not have enough space to have sides with equal length.
