Answer:

Explanation:
Polygon Diagonals are a pattern that follows a specific rule which can be used through a specific formula. Remember that Math focuses on patterns to create equations that help to study them, and this case is not an exception.
The equation for polygon diagonals is

Where
refers to the number of sides of the polygon.
You see, a diagonal is defined as the union between two non-consecutive vertices. For a convex n-sided polygon, there are going to be n vertices, and we can draw
from each vertex, then we multiply this by
, because that's the total number of sides.
In the end, we divide by 2, because with the method described, we will have double number of diagonals.