The sum of all the angles of a quadrilateral is always 360 degrees. We know three of the angles: 90 degrees (right angle), 90 degrees (right angle), and 122. To find the fourth angle add what you know together and subtract the sum from 360 this will give you the fourth angle:
90 + 90 + 122 = 302
360 - 302 = 58
The last angle is 58 degrees!
Hope this helped!