IMAS 2015 Junior Division — Round 1 Question 21

$ABCDEF$ is a regular hexagon. $G$ is the midpoint of $AB$ and $H$ is the point on $AF$ such that $FH=2AH$. If the area of triangle $AHG$ is 1 cm$^2$. What is the area, in cm$^2$, of $ABCDEF$?