Equation practice with angle addition

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Problem

Given
space, m, angle, A, O, C, equals, 104, degree
space, m, angle, A, O, B, equals, 7, x, plus, 30, degree
space, m, angle, B, O, C, equals, 9, x, plus, 42, degree
Find m, angle, B, O, C:
  • Your answer should be
  • an integer, like 6
  • a simplified proper fraction, like 3, slash, 5
  • a simplified improper fraction, like 7, slash, 4
  • a mixed number, like 1, space, 3, slash, 4
  • an exact decimal, like 0, point, 75
  • a multiple of pi, like 12, space, p, i or 2, slash, 3, space, p, i
degree
Do 4 problems