The sum of the interior angles in a polygon increases as the number of sides increases.
You already know that the interior angles of a triangle add up to 180º.
Let's look at this hexagon.
Choose any one corner.
Draw diagonals from the chosen corner to form triangles.
There are 4 triangles inside the hexagon.
4 x 180º = 720º
The sum of the interior angles of a hexagon is 720º.
No. of triangles = No. of sides - 2
Find the number of sides in a polygon whose interior angle sum is 720º.
720 ÷ 180 = 4
No. of sides = No. of triangles + 2
No. of sides = 4 + 2 = 6