When given the vertices's of rectangle, we can find the dimensions by using the distance between points formula.

The distaqnce formula if given by :

D = sqrt(x1-x2)^2 + (y1-y)^2

The formula you need is the following:

If ABCD is rectangle given the vertices's, we know that:

AB = sqrt( xB-xA)^2 + (yB-yA)^2

BC = sqrt(xC-xC)^2 + (yC-yB)^2