Answer:
Step-by-step explanation:
I think you're asking how we use formulas to find areas and volumes.
There's no one area formula; the formula we use to calculate an area depends upon the shape.
For example, the area of a square of side length s is A = s^2.
The area of a triangle with base b and height h is (1/2)*b*h.
Similarly, the choice of formula for the purpose of calculating voume depends upon the shape of the 3-dimensional object.
For example, the volume of a cube with side length s is V = s^3.
The volume of a cylinder with radius r and height h is V = (1/3)πr^2*h.