Paralellogram based pyramid volume Given three points of a paralellogram being
$
P(2,3,4) ; Q(3,1,4); R(2,5,3)
$
I've already calculated the fourth point with
$S(1,7,3)$
Further there's the tip point $Z(5,7,8)$
To get the volume of the pyramid I need to get the distance between the plane that the paralellogram spans and the the tip point.
From my lecture, the parameterform of a plane for the vectors p,v & w would be:

$E=p+ \mathbb{R}\cdot v +\mathbb{R}\cdot w$

Following this, what's the third vector for my example? So far it'd look like this
$$E=PQ+\lambda\cdot PS+ \dots$$
Further: once I have the plane of the parallelogram, is the rest of the way I described correct?

I'd take a cross product, say, $(P-Q)\times(R-Q)$ to get a vector orthogonal to the plane, normalize that to get a normal vector, then form the scalar product of $Z-Q$ with that normal vector and take the absolute value to get the distance of $Z$ from the plane.
