Problem

Source: Second Saudi Arabia JBMO TST 2019, P1

Tags: geometry



On the sides $BC$ and $CD$ of the square $ABCD$ of side $1$, are chosen the points $E$, respectively $F$, so that $<$ $EAB$ $=$ $20$ If $<$ $EAF$ $=$ $45$, calculate the distance from point $A$ to the line $EF$.