I believe the answer would be A.
The greatest common factor of 36 and 81 is 9
Answer:
The two angles are equal where the unequal sides meet.
It can be viewed as a pair of congruent triangles with a common base.
It has 2 diagonals that intersect each other at right angles.
The longer or main diagonal bisects the other diagonal.
A kite is symmetrical about its main diagonal