Which figure would best model the pencil holder to help determine how many pencil holders can fit on a desk?

The best figure to model a pencil holder for determining how many can fit on a desk is a Cylinder.

Explanation: Pencil holders typically have a circular base and a height, resembling a cylinder. Using a cylinder model would allow you to accurately calculate the volume and base area needed to understand how many holders can fit on a flat desk surface, compared to the other shapes listed.