12. As shown in Figure 3, in quadrilateral $A B C D$, $A B=A C=A D$. If $\angle B A C=25^{\circ}$, $\angle C A D=75^{\circ}$, then $\angle B D C$ $=\ldots, \angle D B C=$ $\qquad$
12.12.5 $5^{\circ}, 37.5^{\circ}$.

From the problem, points $B, C, D$ are on $\odot A$, so,
$$
\begin{array}{l}
\angle B D C=\frac{1}{2} \angle B A C=12.5^{\circ}, \\
\angle D B C=\frac{1}{2} \angle C A D=37.5^{\circ} .
\end{array}
$$