Solution:
Given the figure below:
To solve for m∠CAB, we use the chord-tangent theorem which states that when a chord and a tangent intersect at a point, it makes angles that are half the intercepted arc.
Thus,
where
By substituting these values into the above equation, we have
Multiplying through by 2, we have
Collect like terms,
Recall that
Hence, the measure of the angle CAB is