Answer:
Let's add more steps.
step 6: angle AEB measures 360 - 90 -90 - 70 - 39 = 71° Reason, AECF is a quadrangonal and three of its angle measures 90, 90, and (70+39)
step 7: angles AEB and ABE are congruent: reason triangle ABE is isosceles since AE is conruent to AB
step 8 Angle BAE measures 180 -71-71 = 38°: by difference from the sum of the internal angles.
step 9: Angle BAD measures 90 - BAE = 90 - 38 = 52° Reason angles BAD and BAE are complementary.
QED
