by geometry,
[tex]area \: of \: shaded \: region \: = (\: area \: of \: square \: - \: 2 \times (area \: of \: semi - circles)) \div 2[/tex]
[tex] = ({l}^{2} - 2 \times \pi \times {r}^{2} ) \div 2[/tex]
[tex]l = 6 \\ r = l \div 2 = 3[/tex]
[tex] = (36 - \pi \times {3}^{2} ) \div 2[/tex]
[tex] = 3.86[/tex]
area of shaded region = 3.9
