Tricky Triangles

2. a^2 +b^2 = c^2
3. If the corresponding side lengths of two triangles are the same, then the triangles are congruent
5. The measure of an exterior angle of a triangle is equal to the sum of the measures of the two nonadjacent interior angles
7. A triangle with three congruent sides
10. When three or more lines, rays, or segments intersect in the same point
12. A triangle with at least two congruent sides
14. If a ray bisects the angle of a triangle, then it divides the opposite side into segments whose lengths are proportional to the lengths of the other two sides
17. 1/2bh
18. A segment from a vertex to the midpoint of the opposite side
19. The segment connecting the midpoints of two sides of a triangle is parallel to the third side and is half as long as that side
20. If a line parallel to one side of a triangle intersects the other two sides, then it divides the two side proportionally

1. If two triangles are congruent to two angles of another triangle, then the two triangles are similar
4. The sum of the measures of the interior angles of a triangle is 180 degrees
6. If an angle of one triangle is congruent to an angle of a second triangle and the lengths of the sides including these angles are also congruent, then the triangles are congruent
8. A segment, ray, line, or plane that is perpendicular to a segment at its midpoint
9. The perpendicular segment from a vertex to the opposite side or to the line that contains the opposite side
11. If two angles are congruent to two angles of one triangle then the third angles are congruent
13. The point at which the lines containing the three altitudes of a triangle intersect
15. The point where 3 perpendicular bisectors intersect
16. A triangle with no congruent sides