Answer:
The length of the pillow in the shape of a wedge is 4 ft.
Explanation:
The formula for the volume of a wedge is:
![V = (bh)/(2)(L)](https://img.qammunity.org/2020/formulas/mathematics/middle-school/ihsw5zwkbhhvuw85jjwpixkfpowy64xzh2.png)
Where b is the base, h is the height and L is the length.
The volume of the pillow is:
![V = 12\ ^ 3](https://img.qammunity.org/2020/formulas/mathematics/middle-school/fym65cgql9xgk78711jbcor8gra6dt0huv.png)
Then we equate both equations and obtain:
![(bh)/(2)*L = 12](https://img.qammunity.org/2020/formulas/mathematics/middle-school/iz9twoi0dmwhg8t6qb8zr95x4187qrsy1a.png)
We know b and h. So we cleared L.
![b = 3\ ft\\\\h = 2\ ft](https://img.qammunity.org/2020/formulas/mathematics/middle-school/9ens4irl17p0ntcb4zymy5t8t5fskqrjfj.png)
So
![((3)(2))/(2)*L = 12](https://img.qammunity.org/2020/formulas/mathematics/middle-school/rt40gpau1y7xwd2fplzrgc0cfbt1qu5ogw.png)
![(6)/(2)L = 12](https://img.qammunity.org/2020/formulas/mathematics/middle-school/ampdyo1rkp96byir63y99zdzow6zzcxncf.png)
![L = 4\ ft.](https://img.qammunity.org/2020/formulas/mathematics/middle-school/fyeuwbftxdf4lb3zgons368tp3kblf8i40.png)
The length of the pillow is 4 ft.