Geometry

5. A quadrilateral with two pairs of consecutive, equal sides
9. An angle in a circle with its vertex at the center of the circle
11. A triangle with a 90 degree angle and all sides of different length
12. A line segment that has both endpoints on a circle
13. A quadrilateral with four right angles and four sides of equal length
16. A quadrilateral with one pair of parallel sides
17. A triangle with no sides of equal length, all sides have to be different
19. A triangle with a 90 degree angle with two sides of equal length
20. A quadrilateral with all sides of equal length

1. A polygon with four sides
2. A point on a line segment that divides it into two equal parts
3. A six-sided polygon with all sides of equal length and all angles of equal measure
4. A triangle with all sides equal
6. A triangle with two sides of equal length
7. A quadrilateral with two parallel sides, two sides of equal length, and one pair of base angles with equal measure
8. A quadrilateral with four right angles
10. An angle in a circle with its vertex on the circle
14. A quadrilateral with two pairs of parallel sides
15. A five-sided polygon with all sides of equal length and all angle of equal measure
18. The set of points equidistant from a central point