Answer:
117°
Explanation:
Arc ABC (AB + BC) is intercepted by angle D.
Therefore, Arc ABC is 2 × m<D. (Inscribed Angle Theorem)
AB = 91°
m<D = 104°
Let BC = x
Arc ABC = (91° + x)
Thus,
91° + x = 2 × 104°
Solve for x
91 + x = 208
Subtract 91 from both sides
91 + x - 91 = 208 - 91
x = 117
Measure of arc BC = 117°