Let $B$ be the centre of the circle $x^2+y^2-2 x+4 y+1=0$. Let the tangents at two point $P$ and $Q$ on the circle intersect at the point $A(3,1)$. Then 8 . $\left(\frac{\text { area } \triangle A P Q}{\text { area } \triangle B P Q}\right)$ is equal to
