The formula for determining the volume of a cone is:
![V_(cone)=(\pi r^2h)/(3)](https://img.qammunity.org/2023/formulas/mathematics/college/7vr418lvv0s3r7uzkbpivh9c82q7gev9nx.png)
where r = radius and h = height of the cone.
Based on the question, the radius = 30ft, the height = 20ft, and to use π = 3.14.
Let's replace the variables in the formula above with their corresponding numerical value.
![V_(cone)=((3.14)(30ft)^2(20ft))/(3)](https://img.qammunity.org/2023/formulas/mathematics/college/tm9xe4yvja8aqnl9giioohhet9flzjc8ae.png)
Then, solve.
![V_(cone)=(3.14(900ft^2)(20ft))/(3)](https://img.qammunity.org/2023/formulas/mathematics/college/gw0ougjj2dorkqe6n8xk4f6g3th6te9rag.png)
![V_(cone)=(56,520ft^3)/(3)](https://img.qammunity.org/2023/formulas/mathematics/college/7ng8ai027yg4dqgv2jb4m4asa8k97mave9.png)
![V_(cone)=18,840ft^3](https://img.qammunity.org/2023/formulas/mathematics/college/mpet2lr5fdig5z7sxwbwmlojgeg3pvmins.png)
Therefore, the volume of the building is 18, 840 cubic feet.