First you solve for x. 12x+11=x. X would be 1. Then you plug in 1 for x and add the w to the equation. 12(1)+11+w=90. after solving that you will get the total for w. which should be 67°
It could be a building with a triangular top. If the building had a triangular top, then it must have 3 rectangles as its sides. So your answer would be, a building with a triangular top.
