triangles

1. equilateral triangle - it is a triangle with three congruent sides.

2. acute triangle - it is a triangle that has three acute angles

3. equiangular triangle - it is a triangle that has three congruent acute angles.

4. right triangle - it is a triangle with a right angle.

5. interior - is the set of all point inside the figure

6. triangle rigidity - gives you a shortcut for proving two triangle congruent.

7. exterior angles - is formed by one side of the triangle.

8. isosceles triangle - it is a triangle with at lest two congruent sides.

9. scalene triangle - it is a triangle with no congruent sides.

10. auxiliary line - is a line that is added to a figure to aid in a poof.

11. corollary - is a theorem whose proof follows directly from another theorem

12. exterior - is the set of all points outside the figure

13. interior angles - is formed by two side of a triangle.

14. congruent polygons - are two polygons.

15. included angle - is an angle formed by two adjustment sides of a polygon.