I am having trouble setting this problem up.(adsbygoogle = window.adsbygoogle || []).push({});

The problem says: Find a vector N that is perpendicular to the plane determined by the points P(0,1,0), Q(-1,1,2), R(2,1,-1), and find the area of triangle PQR.

I know that the cross product of two vectors is perpendicular to the plane of a and b, so do I just cross the three vectors. I tried PxQ and then (PxQ)xR, but I didn't get the correct answer.

Also, how would you find the area of the triangle? I tried finding the distance of PQ and PR, multipying and dividing by 2, but I still didn't get the correct answer.

Any help?

**Physics Forums | Science Articles, Homework Help, Discussion**

Dismiss Notice

Join Physics Forums Today!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# Homework Help: Calc 3 help. cross product

**Physics Forums | Science Articles, Homework Help, Discussion**