1. Polygon - Closed figure with straight sides.
2. Vertex - Point where sides meet.
3. Vertices - Points where sides of polygons meet.
4. Triangle. - Polygon with 3 sides.
5. Quadrilateral - Polygon with 4 sides.
6. Pentagon - Polygon with 5 sides.
7. Hexagon - Polygon with 6 sides.
8. Octagon - Polygon with 8 sides.
9. Congruent figures - Figures that have same shape and size.
10. Line of symmetry - A line that divides a shape into 2 equal parts.
11. Segment - A straight path from one point to another.
12. Line - Goes on and on in both directions.
13. Ray - Part of a line that goes on and on in one direction has one end point. (Name its endpoint first)
14. Intersecting lines - lines that meet or intersect.
15.Parallel lines - lines that have no points in common, the do not intersect.
16 Right angle - an angle that forms a square corner.
17. Perpendicular lines - when 2 lines intersect to form right angles the lines are perpendicular to each other.
18. Congruent angles - if the tracing of one angle fits exactly in the other angle they are congruent.
19. Parallelogram -opposite sides are parallel and congruent or equal.
20. Rhombus - has 4 congruent sides
21. Rectangle - has 2 pairs of congruent sides and 4 right angles.
22. Square - has 4 congruent sides and 4 right angles.
23. Circle - is named by its center point.
24. Radius - line segment whose endpoints are the center of the circle and a point on the circle.
25. Diameter - a line segment that goes through the center of a circle and whose endpoints are on the circle.