Please tell the answer of 3rd all parts please

Dear Student.

$$\begin{gathered} Since the circle is divided into 16 equal parts so the total angles in the center will be 16. \\ As the angle in the center is 360 so value of each angle would be \frac{360}{16}=\frac{90}{4}=22.5 \\ Hence \angle A_{1}O{A}_2=22.5 \\ \angle A_{1}O{A}_3=2\times \angle A_{1}O{A}_2=2\times 22.5=45 \\ \angle A_{1}O{A}_4=3\times \angle A_{1}O{A}_2=3\times 22.5=67.5 \\ Hence \angle A_{1}O{A}_{12=}11\times \angle A_{1}O{A}_2 \\ Hence \angle A_{1}O{A}_{12} is 11 times \angle A_{1}O{A}_2 \end{gathered}$$
We hope that this answer solves your query.
Regards.