Question 28
As shown in the diagram, part of a triangle $ABC$ is folded along the lines $DE$, resulting in a heptagon $ADECFGH$. If the ratio of the area of this heptagon to the area of the triangle $ABC$ is $5:7$, and the area of the shaded region $DEFH$ is $8$ cm$^2$, find the area of the triangle $ABC$.
