The defining trait of this special type of trapezoid is that the two non-parallel sides (XW and YZ below) are congruent.

Base Angles
The base angles of an isosceles trapezoid are congruent.


Angle $$ \angle ADC = 44° $$ since base angles are congruent

Single $$ \angle ADC = 4° $$ since base angles are congruent

J = 5
Diagonals of Isosceles Trapezoid

X = 9