Distance between two points is (usally) a straight line. Plot (-4,7) and (15,-4), then draw a straight line between them. Now draw a vertical line thru x = -4 and a horizontal line through y = -4. You should see a triangle. The line connecting (-4,7) and (15,-4) is the hypotenuse of a right triangle. You can determine the distance using the Pythagorean theorem or, equivalently, you can calculate sqrt[(-4-15)^2 + (7-(-4))^2] =