The angle measuring 122 degrees is supplementary to the angle next to it.
Supplementary angles are angles that add up to 180 degrees.
180 = ? + 122
Subtract 122 from both sides.
58 = ?
Now we know that the triangle has a 58 degree angle and a 90 degree angle.
58 + 90 + x = 180
Combine like terms.
148 + x = 180
Subtract 148 from both sides.
x = 32 degrees