Points of a 2D Rectangle

Question

Lets say I have a rectangle. 2 points are given to me. A, B, C, D. Lets say A and C are given to us but they are on diagonal opposites. Lets say A(10, 10) B(?,?) C(20,25) D(?, ?). Remember that A and C are the 2 diagonal points given. How would I solve for points B and D?

Answer 1

the x coordinates for B and C must be the same

likewise the y coordinates for A and B must be the same

so B is (20,10)

Similarly, this forces D to be (10,25)

the rectangle is 15 x 10