Answer
Kite
Work Step by Step
When obtuse triangle $XYZ$ is reflected across line $XY$, the resulting figure is a kite. The two congruent angles would be $\angle Z=\angle Z'$. If we were to pretend that this kite looked like a kite you would fly, $\angle Y$ (along with $\angle Y'$) would be the top of the kite, $\angle Z$ and $\angle Z'$ would be the sides and $\angle X$ (along with $\angle X'$) would be were we attach the kite's tail.