Deriving the sum of interior angles in multiple ways

12 questions

1. A ___ is a flat (2D), closed figure made up of straight line segments.
2. What is the size of ∠BCD?
3. A hendecagon has 11 sides. The minimum number of triangles that it could be split into is ___.
4. A hexadecagon has 16 sides. Which calculation would find the sum of its interior angles?
5. Angles around a point sum to ___°.
6. Evaluate the expression 20(x − 2) when x=5.
7. Each time the number of sides of a polygon increases by 1, the sum of the interior angles increases by ___°.
8. The interior angles in 19-sided polygon sum to 3060°. Therefore the interior angles in a 20-sided polygon sum to ___°.
9. Which expression can be used to calculate the sum of interior angles in a polygon by substituting n for the number of sides?
10. A triacontagon is a polygon with 30 sides. Which calculation finds the sum of its interior angles?
11. A tetracontagon is a polygon with 40 sides. Its interior angles sum to ___°.
12. A polygon has interior angles which sum to 720°. The polygon has ___ sides.

License: OGL