if a silos diameter is 10meters and is 20 meters tall then what is the volume of the silo

to find the volume of the slios, or anything round, you need to know the formula, which is:

$${\mathtt{\pi}}{\mathtt{\,\times\,}}{{\mathtt{r}}}^{{\mathtt{2}}}{\mathtt{\,\times\,}}{\mathtt{h}}$$

first, we will do area

radius as you know is half of the diameter

so divide 10 by 2=5

5^2=25

so, $${\mathtt{25}}{\mathtt{\,\times\,}}{\mathtt{\pi}} = {\mathtt{78.539\: \!816\: \!34}}$$

now lets times it by 20 meters, for 20 meters is the height

$${\mathtt{78.539\: \!816\: \!34}}{\mathtt{\,\times\,}}{\mathtt{20}} = {\mathtt{1\,570.796\: \!326\: \!794\: \!896\: \!62}}$$

most accurate answer: 1570.79632679489662 meters

rounded answer (to the nearest whole number):1571 meters

That is excellent Heather , all except you forgot that the units are  $$m^3$$