What is the volume of the parallelepiped with adjacent edges PQ, PR, and PS?

[ahhppull]

Homework Statement

Find the volume of the parallelepiped with adjacent edged PQ, PR, and PS.
P (-2,1,0)
Q (2,3,2)
R (1,4,-1)
S (3,6,1)

Homework Equations

Volume = PQ . (PR x PS)

The Attempt at a Solution

I first found the vectors PQ, PR and PS. Then I did the cross product of PR x PS and then did the dot product of PQ (dot) PR x PS. I got an answer of 6, but the answers in the back of the book says 16. Did I do it wrong? or is the book wrong?

 

[ahhppull]

Nevermind, I found out what I did wrong. I calculated on of the vectors wrong.