Question 13
Let $ABC$ be an isosceles right triangle with right angle at $A$. Let $E$ and $F$ lie on $AB$ and $AC$ respectively, with $\angle ECB = 30°$ and $\angle FBC = 15°$. Lines $CE$ and $BF$ meet at $P$, and line $AP$ meets side $BC$ at $D$. Calculate angle $FDC$.