Question

A quadrilateral has two right angles. The measure of the third angle is 73°.

Answer 1

360 - (90 + 90 + 73)
 360 - 253
   = 107 degrees
to check if the answer is correct, add the numbers together, if it equals 360, then it is right.
  so, 90 + 90 + 73 + 107
                      =360 degrees

Answer 2

The sum of the quadrilateral should be 360 degrees.
We have 3 angle measures given; two ninety degree angles, and one 73 degree angle.
90+90+73 = 253

Then 360-253 = 107

Therefore, the measure of the fourth angle is 107 degrees