Let us write vertices of the given rectangle are PQRS.
Where Q is (c,d) and S is (a,b).
a) Now, we need to find the coordinates of P and R points.
x-coordinate for P is a and y-coordinate of P is d.
Therefore P is (a,d).
On the same way, x-coordinate for R is c and y-coordinate of R is b.
Therefore R is (d,b).
b) Width of the rectangle is difference of y-coordinates of P and S points.
Therefore, width = b - d.
