**This explanation is really confusing to read without an image. Draw a picture and mark out the equal sides. Label the angles as you read the solution.
Call angle XYW = a. Because XW = WY, YXZ = a.
Then, from the exterior angle theorem, ZWY = 2a. Because WY = YZ, angle WZY = 2a
Since the sum of all the angles of a triangle is \(180^\circ\), WYZ = 180-4a
Then, since XY = XZ, 180-4a+a = 2a.
Solve for this to find a = 36