Answer:
x= 45
Explanation:
There are 180 degrees in a triangle
The box in the corner is 90
180-90 = 90
There are 90 degrees left
The lines means that the two sides are equal so the angles must be equal
The two angles are x and x
x+x = 90
2x=90
Divide by 2
2x/2 = 90/2
x = 45