Answer:
40 deg
Explanation:
The vertical sides of the rectangle are parallel, so the triangle is a right triangle.
The triangle is a right triangle, so the acute angles are complementary.
The bottom right angle of the triangle measures 90 - 50 = 40 deg.
The bottom line and the top side of the rectangle are parallel, so corresponding angles are congruent. x and the 40-deg angle are corresponding angles, so they are congruent.
x = 40 deg.