Answer:
KI = 9
Explanation:
Given that triangle IJK has two equal base angles, angle J and angle K, this meets the definition of an isosceles triangle.
An isosceles triangle has two equal angles. Therefore, the side lengths opposite each of the equal base angles of ∆IJK would be of equal lengths.
Given that IJ which corresponds to angle K = 9, and JK, which corresponds to the other 3 angle, therefore, the length of KI which corresponds to angle J would be the same length as the length of IJ = 9.
<k is congruent to <J
IJ = 9, therefore, IJ = KI
KI = 9.