MathNet 2019-part-06 — 184 problems (EN–VI) Question 13

In square $ABCD$ with side $1$, point $E$ lies on $BC$ and $F$ lies on $CD$ such that $\angle EAB = 20^{\circ}$, $\angle EAF = 45^{\circ}$. Find the length of altitude $AH$ of $\triangle AEF$.