This shape is a quadrilateral.
All angles in a quadrilateral add up to 360 degrees.
There is two right angles- right angles measure 90 degrees.
90 + 90 = 180
You are given the the angle 56 so add that to 180.
56 + 180 = 236
To find x, we subtract 236 from 360.
360 - 236 = 124
x = 124 degrees