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).
