Valume of parallelpiped formed by vectors `veca xx vecb, vecb xx vecc and vecc xx veca ` is 36 sq. units.

Answer

`a to r ; b to s ; c to q ; d to p`

Explanation

`[veca xx vecb vecb xx vecc vecc xx veca]=36`
`or [veca vecb vecc]=6`
` Rightarrow` volume of terthedron formed by vectors.
`veca,vecb and vecc is 1/6 [ veca vecb vecc] =1`
`[veca +vecb vecb +vecc vecc +veca] =2 [veca vecb vecc] =12`
`veca-vecb,vecb-vecc and vecc-veca` are coplanar,
`Rightarrow [veca-vecb vecb -veccvecc-veca]=0`