Question

Can you please help me

Answer 1

The arcs AC, AB, and BC must add up to 360º. Then:

arc AC + 120º + 100º = 360º

arc AC = 360º - 120º - 100º = 140º

Now, the inscribed angle ABC is one-half the value of the arc AC. Therefore:

`m\angle\text{ABC}=\frac{140^{}^(\circ)}{2}=70^(\circ)`

(option B)