Question

I need help finding the answer, to this problem.

Answer 1

M<C=180°-(m<A+m<B)=180°-((4x+5)°+(5x-1)°)=180°-(9x+4)°=(180-9x-4)°=(9(20-x)-4)°=(M9-4)°  -> m<C + 4° is multiple of 9 ->  m<C=122° because 122°+4°=126°=9*14° = multiple of 9.