Question

What is the perimeter of this rectangle?
(X1,Y2)
(X2,y2)
(X1,y1)
(X2,y1

Answer 1

(X2-X1)*2+(Y2-Y1)*2

Explanation:

If each point is a vertex of the rectangle, then you'll have the 4 corners:

Left-lower corner: (X1,Y1)

Left-higher corner: (X1,Y2)

Right-lower corner: (X2,Y1)

Right-higher corner: (X2,Y2)

The diference beetween the X and Y values is equal to each side of the rectangle; doing the double sum of each side (X2 - X1) and (Y2 - Y1) it's equal to the perimeter