Sum of Angles in Polygons - The Essential Rules
Here's something brilliant: interior angles in any polygon follow a dead simple formula. Just take the number of sides, subtract 2, then multiply by 180°. So the formula is × 180° where n equals your sides.
Exterior angles are even easier! They always add up to 360° total, so each one equals 360° ÷ n. Whether you're dealing with a triangle or a dodecagon, these rules never fail.
Let's see this in action with an 8-sided polygon (called an octagon). First, we count our sides - that's 8. Then we subtract 2, giving us 6.
Quick Tip: Remember that exterior angles always total 360° - imagine walking around the outside of any shape and you'll always make one complete turn!



