Projection Vector Length

Let

→

a

=

^

i

+

^

j

+

^

k

,

→

b

and

→

c

=

^

j

−

^

k

be three vectors such that

→

a

×

→

b

=

→

c

and

→

a

.

→

b

=1. If the length of projection vector of the vector

→

b

on the vector

→

a

×

→

c

is l, then the value of 3l2 is equal to _______.