Question 174
Let $\overline{AB}$ and $\overline{CD}$ be two diameters of the circle $k$ with centre $S$ and let $\angle BAD = 28^\circ$. The circle centred at $A$ passing through the point $S$ meets the circle $k$ at $E$ and $F$ ($D$ and $F$ are on the same side of $AB$). Find $\angle CFS$. (Matija Bašić)