Please help For 50 points

Answer:
m = 0.875
Step-by-step explanation:
the 3 angles lie on a straight line and sum to 180° , that is
4m + 83 + 4m + 90 = 180
8m + 173 = 180 ( subtract 173 from both sides )
8m = 7 ( divide both sides by 8 )
m = [tex]\frac{7}{8}[/tex] = 0.875