Question 162
Three squares - two squares, $ABCD$ with an area of $30~\mathrm{cm}^2$ and $FHIJ$ with an area of $20~\mathrm{cm}^2$, have their sides $AD$ and $HI$ on a line, as shown in the figure. If the $E$ point of segment $AH$ is such that $BEFG$ is a square, calculate the area of this square. 