A point is dropped at random onto line-segment \(A B\) of length \(a\). Another point is dropped at random on a line-segment \(B C\) of length \(b\). What is the probability that a triangle can be built from the lines: (1) from point \(A\) to the first point; (2) between the two points that were dropped; (3) from the second dropped point to point \(C\) ?