Line charts, sometimes called line graphs, are used most often when you want to display a numerical variable against

time

Step-by-step explanation:

One of the most common graphs is a line graph, also known as a line chart. This graph takes the form of a curve, which is a broken line drawn on an often grid surface. This type of graph is used to illustrate the development of a phenomenon over some time. The curve, drawn by joining the points corresponding to the data, makes it possible to demonstrate an element's variation over time. The title given to the graph will reflect this variation; we will therefore find names like increase, decrease, fluctuation, decline, growth, progression, increase, etc.

We generally place, by convention, the time variable on the horizontal axis (called the abscissa) and the variable corresponding to the phenomenon studied on the vertical axis (called the ordinate).

i believe the answer is the polygon, heptagon.