What is true about a cylinder:

A. The base is equal to 360°
B. There are three parallel planes
C. The surfaces are on the shape on a polygon
D.There is more than one vertex

To determine what is true about a cylinder, let's break down the options:

A. The base is equal to 360°
To examine this statement, we first need to define what the base of a cylinder is. The base of a cylinder is the circular surface at either end. Each base is a circle, and a full circle measures 360 degrees. Therefore, this statement is true. The base of a cylinder does have a measurement of 360 degrees.

B. There are three parallel planes
This statement does not hold true for a cylinder. A cylinder has two parallel planes: one at the bottom and one at the top, which are called the bases. The curved surface connecting the two bases does not create an additional parallel plane. So, this statement is false. A cylinder has two parallel planes.

C. The surfaces are on the shape of a polygon
A cylinder is not a polygon since it doesn't have flat, planar surfaces. Rather, it has a curved surface that wraps around from the top base to the bottom base. Therefore, this statement is false. A cylinder does not have surfaces in the shape of a polygon.

D. There is more than one vertex
In geometry, a vertex is a point where multiple lines or edges meet. In the case of a cylinder, there are no corners or points where edges meet since it has curved surfaces. Therefore, this statement is false. A cylinder does not have vertices.

In summary, the correct statement about a cylinder is: The base is equal to 360° (Option A).