A triangle has vertices A (2, -2), B (-2, 5), and C (-4, 2).
1) The slope of line segment AB is _____ units.
2) The slope of line segment BC is _____ units.
3) The slope of line segment AC is _____ units.
4) By looking at these slopes, you can tell that triangle ABC is a right triangle, because
(_____)(_____) = _____.