Vector product and planes
is a vector perpendicular to both and , of length . A plane is fixed by a point and a normal : , or . Substituting a line into a plane finds where they meet.
≈ 50 minShortest distances and triple products
The shortest distance is always along a perpendicular. From point to plane : . Between skew lines: project the join of two points onto . The triple product is the volume of the parallelepiped.
≈ 45 min