Move the slider to change the number of sides on the polygon - can you use this information to help you find a rule to work out the sum of interior angles in a polygon?

What is the sum of interior angles for a triangle?[br][br]Can you see a relationship between the number of sides of a polygon and the amount of triangles that "fit" inside it?[br][br]How can this help you to work out the sum of interior angles for another polygon?[br][br]Can you find a rule to work out the sum of interior angles in any polygon?