Meg is calculating the amount of water that a cylinder will hold is that surface area or

Let us first define surface area and volume. Surface area is the sum of the areas of the faces of a three-dimensional figure. In other words, surface area is just the outside part of the figure. Volume is the space an object occupies, so essentially its size.

Meg is trying to calculate the amount of water a cylinder can hold; that means she is calculating the how much space the cylinder has inside it. Meg is finding the cylinder's volume.