The picture gives us that two sides are congruent. We can see that an <em>angle</em> is congruent as well because they share a common point at their tip.
If we look at just the area of intersection, it looks like an X. Think of the X as two lines intersecting. Each side equals 180°, and because both triangles are made up of those sides, we can conclude that the angles are congruent as well.
