Question 23
$ABCD$ is a square sheet of paper with sides of length 6. The paper is folded along a crease line $EF$ so that points $A$ and $B$ now lie on $A\prime$ and $B\prime$ respectively as indicated in the diagram. If $H$ is the intersection of $A\prime B\prime$ and $BC$, what is the perimeter of the triangle $A\prime CH$?
