Can someone me with this and explain how they got the answer, and you!

The answer is 37 degrees. That is a 90 degree angle so if you subtract  90-53, you get 37.

See that little box in the angle? That means it is a right angle. A right angle is 90 degrees always. If the angle is split into two parts and one side is 53 degrees, the other side is the rest of the 90 degree angle. The two angles have to add together to make the 90 degree angle, so you just subtract 53 from 90 and get 37 degrees.