Question

HELP!?! If line AD is a tangent to circle B, what is the measure of BCA?

Answer 1

Assuming the entire line is tangent to the circle, as it appears, I do not believe your question is answerable as it is posed, for the reason that point "A" can be made to intersect the line at any point throughout its length. That said, graphically, it appears that point "A" is 1/2 way between "C" and "D" - but "appearances" do not an accurate calculation make.