Midpoint: of a line segment AB is the point that is equidistant from the endpoints A and B. d(A, B) = √ (x1 − x2)2 + (y1 − y2)2. It does not matter in what order you subtract the x−coordinates or the y−coordinates. a2 + b2 = c2.
If you don't understand, maybe get someone else to explain the coordinates to you.
