Question 824874
x = angle
(90 - x) = complement
(180 - x) = supplement
(180 - x) = (9/4)(90 - x)
 180 - x = 810/4 - (9/4)x
multiply each side by 4
4(180 - x) = 810 - 9x
720 - 4x = 810 - 9x
add 5x to each side
720 + 5x = 810
subtract 720 from each side
  5x = 90
divide each side by 5
 x = 18