Question 12
Let $ABCD$ be a square piece of paper such that $M$ and $N$ are the midpoints of $AB$ and $CD$, respectively. Let $P$ be a point on $AM$ such that if it is folded along $DP$, then $A$ lands on point $Q$ on line segment $MN$. What is the angle measure, in degrees, of $\angle ADP$?