Step-by-step explanation:
Width of rectangle = 7 cm
[tex] \because [/tex] width of rectangle is equal to the radius of each semicircle. 
[tex] \therefore [/tex] radius of each semicircle (r) = 7 cm. 
[tex] \therefore [/tex] Diameter of each semicircle = 14 cm
[tex] \therefore [/tex]  Length of rectangle = 3 x 14 = 42 cm. 
[tex]Area \:  of  \: shaded  \: region \\  = Area \:  of  \: rectangle \\  \:  \:  \:  \:  \:  - 3  \times area \: of \: one \: semicircle \\  = l \times w - 3 \times   \frac{\pi {r}^{2} }{2}  \\  \\  = 42 \times 7 - 3 \times  \frac{3.14 \times  {7}^{2} }{2}  \\  \\  = 294 - 3 \times  \frac{3.14 \times  49 }{2}   \\  \\   = 294 - \frac{461.58}{2}   \\  \\  = 294 - 230.79 \\  \\   \purple { \boxed{ \therefore \: Area \:  of  \: shaded  \: region = 63.21 \:  {cm}^{2}}}  \\ [/tex]