It is a simple question. Let's consider two equations first for the scalar product second for the vector product. Let the angle be t.

Scalar product = a.b.cos t = 8

Vector product = a.b.sin t = 8 root 3

Dividing second equation by first equation we get, sin t/cos t = root 3

We know sin t/cos t = tan t.

So, tan t = root 3 ; and that is the case when angle = 60 degree.

So, t(angle)=60 degree.

Hey Jayesh,

The solution is very simple

since, ab=8

absinD=8root3

therefore, 8sinD=8root3

sinD=root3

This is impossible

since, -1<=sinx<=+1

So i think vector product should be 4root3.

Hope this helps you!