geometry

3. line-a line containing the circumcenter, centroid and orthocenter of a triangle
4. of a triangle- the perpendicular segment from the vertex to the line centroid of a triangle- the point of concurrency of the three medians of a triangle
7. of concurrency- a point where three or more lines intersect.
8. of a circle-a region inside a circle bounded by two radii of the circle.
10. circle- a circle that contains all polygons.
11. length-the distance along an arch measured in linear units.
12. proof- a style of proof that uses boxes and arrows to show the structure of a proof. paragraph proof- a style of proof in which statements and reasons are presented in paragraph form

1. reciprocal-the opposite the reciprocal of a number
2. of a triangle- the point of concurrency of the three altitudes of a triangle
5. of a triangle- the point of concurrency of the three perpendicular bisectors of a triangle.
6. of a triangle- a segment whose endpoints are a vertex of the triangle and the midpoint of the opposite side
9. point of concurrency of the three angle bisectors of a triangle.
10. lines-three or more lines that intersect at a point