(c) $60^{\circ}$ We have $\angle A=75^{\circ}$. Therefore, $\angle C=75^{\circ}$. Using angle sum property in $\triangle B C D$, we obtain: $\angle C B D=60^{\circ}$.
Need a full question paper?
Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.