Final answer:
To prove AB is a perpendicular bisector of CD in triangle DAC, Kiran needs to know that AB bisects CD and forms a right angle at the point of intersection.
Step-by-step explanation:
To show that segment AB is a perpendicular bisector of segment CD in isosceles triangle DAC, where AD is congruent to AC, Kiran would need to know two additional pieces of information:
- That AB intersects CD at its midpoint, thereby bisecting CD.
- That the angle formed by AB and CD at their intersection is a right angle (90 degrees), demonstrating perpendicularity.
Once these two criteria are met, it can be concluded that AB is indeed a perpendicular bisector of CD. Knowing that the base angles of an isosceles triangle are congruent is a starting point, but by itself, it does not provide enough information to determine the relationship between AB and CD.