The value of q is 12 yards.
To find the value of q, let's use the formula for the surface area of a cube:
![\[ \text{Surface Area} = 6s^2 \]](https://img.qammunity.org/2022/formulas/mathematics/high-school/tdc53g9p8k7k22ib1gzu9l3z118fyqt46m.png)
where s is the length of a side of the cube.
Given that the surface area is 864 square yards, we can set up an equation:
![\[ 6s^2 = 864 \]](https://img.qammunity.org/2022/formulas/mathematics/high-school/4lsvtdccd777ej6089pyvmc84pncq5zx1k.png)
Now, solve for s:
![\[ s^2 = (864)/(6) \]](https://img.qammunity.org/2022/formulas/mathematics/high-school/r5ez3b81n6pcm7sjptn9l7eer21uy6yh1f.png)
![\[ s^2 = 144 \]](https://img.qammunity.org/2022/formulas/mathematics/high-school/cyurmjurnppbfcuwcol6kswxahf42o4ju6.png)
![\[ s = 12](https://img.qammunity.org/2022/formulas/mathematics/high-school/eb4b5uujek218ixdiopbp5o6k0h16szxsx.png)
Since q represents the length of a side of the cube,
.
Therefore, the value of q is 12 yards.