Geometry Terms

4. A combination of three or more coplanar segments that meet only at endpoints. At most, two segments meet at one endpoint and each segment meets exactly two other segments.
5. The part of a straight line considered as originating at a point on the line and extending in one direction from that point. You can name a ray using it’s starting point and one other point that is on it.
7. The intersection point of two sides of a plane figure. The meeting place for two mathematicians.
8. A statement that describes a fundamental relationship between basic terms of geometry. They are accepted as true without using a proof.
10. A set of points that has infinite length and width but no height. Named with a capital letter.
11. Angles Angles that occupy the same position on the unit circle. These are negative and positive.
14. A logical argument in which each statement you make is supported by a statement.
15. Equations that state that two ratios are equal.
17. A polygon with four sides. For example: squares, rectangles, and trapezoids.
18. A straight line extending from the center of a circle or sphere to the circumference or radius. Half of the diameter.
19. The figure formed by three segments joined by three noncollinear points. Each of the three points is a vertex and the segments are the sides.

1. A solid or shape which has an indentation. There is at least one line segment connecting interior points which passes outside of the figure.
2. Root A nonnegative that must be multiplied times itself to equal a given number.
3. Segment joining the two base planes and perpendicular to both. Also known as the height.
6. The shape formed when two rays meet a common point. Usually measured in degrees.
9. Operation that alters the form of a figure. For example, translations, reflections, dilations, and rotations.
10. Theorem An equation relating to the length of the sides of a right triangle. The sum of the squares of the legs of a right triangle is equal to the square of the hypotenuse.
12. The line segment between two points on a given curve. The _________ of an angle is the length of the _________ separated by a central angle.
13. A branch of mathematics that deals with points, lines, planes, and solids and examples of their properties. This type of math is great for architects.
16. A transformation that changes the size of a figure. It can become larger or smaller, but the shape of the figure never changes.