geometry words

1. a logical argument in which each statement you make is supported by a statement that is accepted as true
2. the point of concurrency of the perpendicular bisectors of a triangle
4. points that lie on the same plane
6. The point of concurrency of the altitudes of a triangle
9. The steepness of a line on a graph
11. A figure formed by two rays with a common endpoint
14. less than 90 degrees
15. Where two lines meet
17. The distance around a circle
18. geometry equals 90 degrees

1. the sum of the lengths of the sides of a figure
3. A part of a line, with one endpoint, that continues without end in one direction
4. Being equal to another
5. points that lie on the same line
7. a line that intersects two or more lines
8. the measure of a region's size on a surface.
10. if they intersect at a single point. They are in contrast to parallel lines.
12. a statement that can be proven
13. Angle above 90 and under 180 degrees
16. a ray that divides an angle into two congruent angles