Find point farthest from line

Question

I have an array of points, as well as two more points (A and B). The last two points form a line, and I'm trying to find which of the points in my array are furthest from the line. How would I do this in Java?

I'm wondering if it's something along the lines of finding the distance from A and B, but that doesn't sit well in my head.

Additional info: I think it's a line segment. Given this is QuickHull, I don't know if it makes a difference. I've never been the greatest when it comes to math and formulas, so more explanation is better. Thanks!