Area of a Parallelogram from 3D points

[somebodyelse5]

Homework Statement

Find the area of the parallelogram with vertices:

P(0,0,0), Q(-3,0,-1), R(-3,1,0), S(-6,1,-1)

Homework Equations

A=BH

The Attempt at a Solution

I think I know why this is incorrect, but i don't know what else to try.

I found vector PQ and called it a, vector PR called it b, vector PS called it c.
Then did a dot (b cross c)=3 but that's incorrect.

I basically found the volume, but idk how to find the area.
Any suggestions I should try?

 

[tiny-tim]

Hi somebodyelse5!

The area of a parallelogram is (±) one side "cross" the next side.

 

[somebodyelse5]

Hi somebodyelse5!

The area of a parallelogram is (±) one side "cross" the next side.

Thanks! wow that was a pretty stupid question on my part, I should have known how to do that, especially since that's the first step in finding the volume of a parallepiped (sp?)

Thanks, got it figured out!