Final answer:
The proportion that corresponds to the angle bisector theorem in triangle proportionality is the Angle-Side Relationship.
Step-by-step explanation:
The proportion that corresponds to the angle bisector theorem in triangle proportionality is the Angle-Side Relationship. In an isosceles triangle, the angle bisector divides the base into segments that are proportional to the lengths of the two congruent sides. This relationship can be expressed as:
If AD is the angle bisector of ∠A in triangle ABC:
(AB)/(AC) = (BD)/(CD)