1. NON-POLYGONS
POLYGONS
QUESTION
WHAT IS A POLYGON? 1

2. An Investigative Activity!
L.O. To be able to find the sum of the interior angles of a polygon
An Investigative Activity!

5. Investigation
Choose one vertex and draw as many diagonals as possible to the other vertices to form triangles
Complete each column in the table
When you are done try to answer the following questions:
What is the relationship between the number of sides of a polygon and the number of triangles formed from the diagonals?
Can you predict the angle sum of an Icosagon (20 sides)?
Explain your reasoning using your table.

6. Discover the Formula
Can you write a rule that will give the sum of the angles for any polygon?
(n sides)
𝑆𝑢𝑚 𝑜𝑓 𝑖𝑛𝑡𝑒𝑟𝑖𝑜𝑟 𝑎𝑛𝑔𝑙𝑒𝑠 = 𝑛−2 ×180
where 𝑛 is the number of sides