# Show that four points lie on a plane

1. Aug 8, 2014

### toupee

1. The problem statement, all variables and given/known data
(2; 0; 1); (-1; 2; 3); (3; 2; 2) and (3;-6;-3)

2. Relevant equations

PS→⋅(PR→×PQ→)=0

3. The attempt at a solution

Hi all, I am just wondering if my calculations are correct, and in fact these points do not lie on a plane. My answer is = 50 and i am not confident. Can anyone help me please?

Last edited by a moderator: Aug 8, 2014
2. Aug 8, 2014

### Orodruin

Staff Emeritus
It would be much easier to judge if what you are doing is correct if you actually showed us what you are doing.

Edit: Also, the points do lie in a plane - any solution not resulting in this is going to be wrong.

Last edited: Aug 8, 2014
3. Aug 8, 2014

What is 50?

ehild

4. Aug 8, 2014

### toupee

I have miss-read the question. All it is asking me to do, is prove that these points lie in the same plane. May i ask how?

5. Aug 8, 2014

### Orodruin

Staff Emeritus
If this is a homework problem or problem in a course you are taking there should be a description of how to determine this in your course literature. Have you tried applying that?

6. Aug 8, 2014

### HallsofIvy

Staff Emeritus