10. The figure below is a face of a Slake, $A B C D E 、 J K L I F 、 G H M N O$ are regular pentagons, $F G H I$ is a square, $A B / / F G, \triangle E K L 、 \triangle C M N 、 \triangle B O N$ have areas of 2, 3, 4, respectively, then the area of $\triangle A K J$ is $\qquad$ .
$3$