So lets ABCD are the sides of the square and AB=CD, AC=BD and the Angle ABC = 90 so therefore by making a diagonal we can use the SAS or SSS congruency for two triangles, so we can prove two triangles are equal and that is why the shape is square.
The value do you mean absolute value if you do it would be 4
If you have supplementary angles, that means that the angles have to add up to 180°. So x+(x+8)=180° So I would combine like terms 2x+8=180 Now subtract by 8 on both sides which gives me 2x=172 now divide by 2 and x equals 86°! I hoped this helped you!
