geometry crossword

1. the point of concurrency of the three medians
3. switch hypothesis and conclusion
5. segment that connects the midpoints of 2 sides of a triangle
8. bisector:a segment, ray, line, or plane that is perpendicular to a segment at its midpoint
11. angle inside of a polygon
15. angles that are in the same position
17. the point of concurrency of the 3 perpendicular bisectors of a triangle
18. the perpendicular segment from a vertex to the opposite side or to the line that contains the opposite side
19. a line that intersects 2 or more co-planar lines at different points
20. the altitudes of a triangle are congruent and meet at a point called this

2. angle formed outside of a polygon when the original sides are extended
4. do not intersect and are not co-planar
6. a segment from a vertex to the midpoint of the opposite side
7. of concurrency: the point where 3 or more lines, rays, or segments intersect
9. all sides are congruent
10. endpoint of a side
12. the segment connecting the midpoint of 2 sides of a triangle is parallel to the third side and half as long as the side
13. negating and using the converse
14. the point of concurrency of the 3 angle bisectors of a triangle
16. negate hypothesis and conclusion