Question 4
The diagram to the below shows three squares $EFGH$, $KLMN$ and $PQRS$ inside a rectangle $ABCD$. The areas of the three squares are $1\text{ cm}^2$, $9\text{ cm}^2$ and $4\text{ cm}^2$ respectively. What is the sum of areas of the shaded regions in $\text{cm}^2$?
