If a° > 90°, find the range of values that the expression y - x must be.

Question

a°=180-y°+x°

 a is an exterior angle of a triangle with the two remote interior angles being 180-y and x.

Answer 1

a = 180° - y + x

a > 90°

180° - y + x > 90°

180° > 90° + y - x

90° > y - x