geometry

3. – The amount of space occupied by a three-dimensional object.
7. – The point that is equidistant from all points on a circle.
8. – A part of a line with one endpoint, extending infinitely in one direction.
9. – The figure formed by two rays with a common endpoint.
10. – A flat, two-dimensional surface that extends infinitely in all directions.
11. – A line segment from the center of a circle to any point on its circumference.
14. – A triangle with all sides of different lengths.
15. – The point where two or more lines, rays, or segments meet.
17. – The measure of the space inside a two-dimensional figure.
19. – A closed figure formed by a finite number of straight line segments.
20. – A line segment connecting two points on a circle.

1. – A triangle with exactly two sides of equal length.
2. – The longest side of a right triangle, opposite the right angle.
4. – A chord that passes through the center of a circle, twice the radius.
5. – A polygon with three sides and three angles.
6. – Lines in the same plane that never intersect, no matter how far they extend.
12. – A polygon with six sides and six angles.
13. – A straight path extending infinitely in both directions with no endpoints.
16. – A transformation producing a mirror image of a figure over a line.
18. – Repeated here; see #8.