From Lesson 6-5 Make a Table
Problem: How many diagonals does a 13-gon have?
Suggestion: Find a pattern from easier polygons like the ones below
Do this on a spreadsheet. Can you find a pattern to continue column B without drawing the figure and counting the diagonals?
Here’s what you should get
Can you write a formula in cell B16 (without filling in the previous cell’s contents) that will give you the number of diagonals?