Answer: 28 degrees
Explanation
angle A = angle E because the corresponding pieces are congruent.
Notice that A and E are the first letters mentioned of ABCD and EFGH respectively.
Because of this, we form the equation y^2-10 = 90 which leads to y^2 = 80.
We don't need to isolate y itself.
angle H = 2y^2 - 132 = 2*80-132 = 28 degrees which is also the measure of angle D.
Notice that D and H are the last letters mentioned of ABCD and EFGH respectively.