vertices of a rectangle?

Question

i feel so dumb when i ask these questions all the time, but here it goes:

Rectangle ABCD has vertices at A(4,7), B(3,1), and C(-3,2).
i have the equations for AB and BC, but i have to find one for CD and AD as well, and I'm not sure how to find the vertice for D if i even have to. I have to find the equation of the line that contains CD and find the equation of the line that contains AD.

Answer 1

It helps to do some sketching. If you do that, you would find that D is at (-2,8). If you note, the y coord of C is 1 more than for B and the x coordinate of C is 6 less than for B, and the x coordinate of A is one more than for B.

So for each line you have two points, which is enough to solve your problem.