21. Determine the area of the region

$ABCD$ is a square of side 7.8 $cm$. $P$, $Q$, $R$ and $S$ are the mid-points of $AB$, $BC$, $CD$ and $AD$ respectively. When the four arcs drawn intersect at $P$, $Q$, $R$ and $S$, find the area of the unshaded region. [Use $\pi$ $=$ $3.14$]

 

 

The area of the unshaded region $=$102.7547.7668.3283.52  $cm^2$