Answer:
the last option of 135°.
Explanation:
The total degree of the rectangle is 360°. But it was sliced, so with the remaining measurements, subtract each of them from 360°.
90°+90°+45°+x°=360°
225°+x°=360° add all of the values on the left side, then subtract 225 on both sides to solve for the value of x°.
x°=135°