Look at the picture.
The formula of the area of a trapezoid is :
[tex]A_T=\dfrac{base+base}{2}\cdot height[/tex]
We have:
[tex]base=12m;\ base=5m;\ height=2\cdot3m=6m[/tex]
Substitute: [tex]A_T=\dfrac{12+5}{2}\cdot6=17\cdot3=51\ m^2[/tex]
The formula of the area of a circle is :
[tex]A_C=\pi r^2[/tex]
We have [tex]r=3m[/tex]
Substitute: [tex]A_C=\pi\cdot3^2=9\pi\ m^2[/tex]
The area of the shaded portion of trapezoid: [tex]A=A_T-A_C[/tex]
Substitute: [tex]A=(51-9\pi)\ m^2\approx(51-9\cdot3.14)\ m^2=22.74\ m^2[/tex]
