More ACT and SAT Math Formulas.

Here are a couple more formulas you should know for the ACT and SAT...

​The sum of the internal angles for a polygon with ​n​ sides (an "n-gon") is (n-2) * 180 degrees. For example, the sum of the internal angles in a pentagon is (5-2) * 180 degrees = 540 degrees.

​The sum of the external angles, taken one per vertex (corner) for any polygon, no matter how many sides it has, is 360 degrees. For two external angles per vertex, multiply 360 by 2 to get 720; for 3, multiply 360 by 3 to get 1080 degrees.