Australian Intermediate Mathematics Olympiad 2020 Question 4

$ABCD$ is a square of side 10 cm. $E,F,G,H$ are points on the sides $AB,BC,CD,DA$ respectively. Given that $EB=FC$, $CG=DH$, and $CG-EB=4$ cm, find the area of the quadrilateral $EFGH$ in square centimetres.