To find the interior angle measure of one angle of any regular polygon, use this formula. Let n= the number of sides of the regular polygon
\(\frac{180(n-2)}{n}\)
Let's see this expression in action:
| Number of Sides | Name of Regular Polygon | Interior Angle Measure | |
| 3 | Triangle | \(\frac{180(3-2)}{3}=\frac{180*1}{3}=60\) | |
| 4 | Quadrilateral | \(\frac{180(4-2)}{4}=\frac{180*2}{4}=90\) | |
| 5 | Pentagon | \(\frac{180(5-2)}{5}=\frac{180*3}{5}=108\) | |
| 6 | Hexagon | \(\frac{180(6-2)}{6}=\frac{180*4}{6}=120\) |