You could reverse the triangle to look like a regular right triangle, making 7 on the bottom and 15 as the hypotenuse.
The height is about 13.2664991614216, which is rounded to 13
As long as we know the base and the hypotenuse we can calculate the value of x. If you do the math you get 62.181860715346076° which is rounded to 62°
The answer is 62°