Curriculum
Mathematics — First Preparatory
Unit 1: Numbers
0/10
Unit 2: Algebra
0/4
Unit 3: Statistics
0/6
Text lesson
Polygons
Polygons
Common mistakes
Common mistakes
- Using (n − 2) alone without multiplying by 180°.
- Confusing the sum of the interior angles with the sum of the exterior angles. The exterior sum is always 360°.
- Forgetting to divide the total by the number of sides when a regular polygon’s angle is asked for.
- Counting the sides as diagonals. Diagonals join only non-adjacent vertices.
- Applying the diagonal rule to a triangle. A triangle has no diagonals, because every pair of its vertices is adjacent.
Polygons · 4 / 5