If the ratio of the roots of $ax^2+bx+c=0$ is equal to the ratio of the roots of $px^2+qx+r=0$ and if $D_1,\:D_2$ are their discriminants respectively, then $D_1:D_2=?$

Question

$\begin{array}{1 1} a^2:p^2 \\ b^2 :q^2 \\ c^2:r^2 \\ b:p \end{array} $