What is the volume of a rectangular solid 7m by 8m by4m?

Answer 1

I wonder if it is a proof question, because it is a formal way to prove the volume formula.

But otherwise, it is really straight forward, it even said it in the question: It's 7m by 8m by 4m. whatever that gives.

As a non verbal convention, when we describe a geometric shape, we describe it's dimensions "by" each other. In particular 2D shapes we say "base by height" which is exactly it's area (and a factor). Similarly for 3D we say "length by height by width" which is measurment of its volume (with a factor). The only thing tricky would be recognize the shape and determine what that "factor" is.

If you want a functional proof of the formula, message me.