Answer:
126 degrees
Step-by-step explanation:
Making a system of equations of both given equations because they are vertical angles is 90-12b = -3b+63. Solving this equation gives you b = 3. Take this value and plug it in to 90-12b to get 90-36 = 54. Take that value and subtract it from 180 degrees because the requested angle is supplementary, so the other side is just 180-54 is 126 degrees. Hope that helps!
