11. The two interior angles of a kite that are on opposite sides of the symmetry axis are equal. 12. One interior angle in a regular triacontagon is 168? meaning that one exterior angle would be 12? 13. The sum of the interior angles of any non-self-intersecting 257-gon is 91800? 14. The sum of the interior angles of any non-self-intersecting 65537-gon is 23592600? 15. The third, fourth and fifth are short and the sixth and seventh extending nearly to the interior angle . 16. For example, no matter how a triangle is transformed, the sum of its interior angles is always 180? 17. Equivalently, a convex quadrilateral is cyclic if and only if each exterior angle is equal to the opposite interior angle . 18. This contradicts Proposition 16 which states that an exterior angle of a triangle is always greater than the opposite interior angles . 19. Finally, tweak the interior angle at the vertex of the two shortest sides so it is slightly greater than 180? 20. The sum of its interior angles ( two acute and two reflex ), as with any crossed quadrilateral, is 720?
