Well, if you are measuring the area or volume of a figure, then there are different formulas when it comes to spheres, triangles, squares, and etc.
Basically the formulas different, and you need the right formula that goes with that specific shape.
Example: I have a triangle and all its sides are 3 cm. But I only tell you that all my figure's sides are 3 cm. You would need to know the shape of it to do anything worthwhile with that information.
