Answer:
42 degrees
Step-by-step explanation:
Angle A is an inscribed angle of the arc BC.
As a rule of thumb, remember that the measure of all inscribed angles is half of the measure of the intercepted arc.
In this case, the intercepted arc is BC, which we know is 84 degrees. So, if the inscribed angle is half of that, then angle A = 84/2 = 42 degrees.
Hope this helps!
