If `|vecaxxvecb|^(2)+(veca.vecb)^(2)=144and|veca|=4,"then "|vecb|` is equal to ……..

Explanation

Since `(veca xx vecb)^(2) + (veca. Vecb)^(2) = 144` if the angle between `veca and vecb is theta`. Then
`|veca|^(2)|vecb|^(2) sin ^(2)theta + |veca|^(2).|vecb|^(2)cos^(2)theta=144`
`or |veca|^(2)|vecb|^(2) = 144`
`or |veca||vecb|= 12`
`or 4 |vecb|=12`
`or |vecb|= 3`