Hi Mike,

The above posts sound alot quicker than my solution which was:
Take the equation for a circle (x^2 + y^2 = r^2)
Take the equation for a straight line (y = mx + c)
these 2 lines are coincident when the x from the circle = x from the line, and y from the circle = y from the line, therefore substitute one equation into the other to create a quadratic equation (x^2 + mx + [c-r^2] = 0. Solve this using the quadratic formula to give x. Substitute back into either of the above to give y. This gives the 2 sets of coordinates of where the circle and line intersect.

This is a bit more generic than the solutions above, so should work for other related shapes, but is more complex!