The given points A, B, C are the vertices of a triangle. Determine the vectors `vec(AB),vec(BC)` and `vec(CA)` and the lengths of these vectors in the following case.
A(8,6,1), B(2,0,1), C(-4,0,-5)

Explanation

`vecAB` = `-6hati-6hatj`
`vecBC` = `-6hati-6hatk`
`vecCA` = `12hati+6hatj+6hatk`
AB = `|vecAB|` = `sqrt(36+36)` = `6sqrt2`
BC = `|vecBC|` = `sqrt(36+36)` = `6sqrt2`
CA = `|vecCA|` = `sqrt(144+36+36)` = `sqrt(216)` = `6sqrt6`