You need to find the volume of extra space. The space has the shape of a right rectangular prism.
The formula for the volume of a right rectangular prism is
![V=A\cdot h](https://img.qammunity.org/2023/formulas/mathematics/college/lravfi7um4lyy9jfli69fvewb5oh452wq0.png)
Where A is the floor area and h is the height of the ceiling
If Maggie puts a 7 ft ceiling then the volume of the space will be
![V1=3000ft^2\cdot7ft=21000ft^3](https://img.qammunity.org/2023/formulas/mathematics/college/mq2ycjck286eitftwr3l9ji0lt3vck0m10.png)
But if she puts an 8 ft ceiling instead, the volume will be
![V2=3000ft^2\cdot8ft=24000ft^3](https://img.qammunity.org/2023/formulas/mathematics/college/28bf57qj5o8gqt8th60ap2cwa73m9birsl.png)
Then the extra space she will have to heat and cool will be
![V2-V1=24000ft^3-21000ft^3=3000ft^3](https://img.qammunity.org/2023/formulas/mathematics/college/1euydazvw3963eab0h5959164r8fq780mu.png)
Maggie will have to heat and cool 3000 ft³ more of space if she puts an 8 ft. ceiling