We know that cylinder is a 3D figure, and that 3D figures have 3 dimensions each. Different shapes have different parameters as well.
For example, parameters of the following:
- Cuboid - Length, Breadth, Height
- Cone - Radius, Height, Slant Height
Similary, what are the parameters of a cylinder. I know 2 of them - Height & Radius. What is the third (or any other) one?
Update: I meant to say parameters instead of dimensions
You're confusing 3 dimensions and the number of parameters a 3D object may have.
Every 3D object has a set of parameters that need to be determined to uniquely determine the magnitude of the object's dimensions. For a cuboid, there's three - length, height and breadth. For a cone and cylinder, you only need two. For a sphere, it's just one (its radius).
However, every 3D object extends in all 3 dimensions - x, y, and z - no matter how many parameters they have.
Hope that helps!
Updated:
As I said earlier, a cone also has only two parameters. And as you determined yourself even a cylinder has only two. As I've proved above in my answer a 3D object may not necessarily have 3 parameters as well.