Hey there! I'm happy to help!
To find the volume of a cylinder, you multiply the base by the height.
First, we find the base. The base is a circle. To find the area of a circle, you square the radius and multiply it by pi (we will use 3.14). The radius is half the diameter.
6.5/2=3.25
We square this.
3.25²=10.5625
And multiply by 3.14
10.5625(3.14)=33.16625
Now we multiply this by the height.
33.16625(12)=397.995
Therefore, the volume of this silo is 397.995 cubic meters.
Have a wonderful day! :D