In the given figure, ABCD is a square of side `10` cm and semicircles are drawn with each side of the square as diameter. Find the area of the shaded region.
[ Use `pi=3.14`]

Explanation

Let us mark the unshaded regions as I, II, III and IV as show in the given figure.
Let these regions meet at a common point `O`. Then,
(area of I) `+` (area of III)
`=` ar(sq ABCD) `-` {ar(semicircle AOD) `+` ar(semicircle BOC)}
`={(10xx10)-(1/2xx3.14xx5^(2)+1/2xx3.14xx5^(2))}cm^(2)`
`=(100-78.5)cm^(2)=21.5cm^(2)`
Similarly, (area of II) `+` (area of IV) `=21.5cm^(2)`
Area of shade regioin `=` ar (sq ABCD) `-` ar(`(I+II+III+IV)`
`={(10xx10)-(2xx21.5)}cm^(2)`
`=(100-43)cm^(2)=57cm^(2)`