Answer:
55°
Explanation:
In the triangle towards the bottom-left, we can see that it is an iscosceles triangle, which means that the two angles opposite of those two sides are also equal. Along with this, a triangle will also only have 180° for the sum of all of its angles.
When you put another x in the angle next to the 37°, you get an equation similar to:

x in this case will then be 55 degrees.