Here we have a donut chart. They are similar to a pie chart, but with a hole in the center. DUH!
Three equal slices are available, and each one is adjustable for color, how big a slice it is, and how fat it is!
This makes this method easily adaptable to a dynamic situation, where values are changing over time. If the values are placed in a database that can be accessed, you have a tool that automagically updates a web page.
This path (arc) is centered on the circumference of a circle, so the diameter of the 'hole' changes as the stroke-width is changed. The beginning of the slices (0°) is at the top: 12:00 and moves clockwise.