The language that is used to identify these types of problems must be very specific because this is a very specific use case. When they want you to apply this cross-sectional area method, they will be very direct with the language, and you should expect to see the term “cross-section” used.
Other language to be aware of is the use of the term “solid”. They use the wording “solid” when they are wanting you to find the “volume” of a shape.