Geometry Vocabulary

5. Figures (usually points) that lie on the same line.
6. A part of a line that consists of two points, called endpoints, and all the points between them.
9. Two angles in the same plane that have a common vertex and a common side, but no common interior points.
10. A triangle with a right angle. The side opposite the right angle is called the hypotenuse. The other two sides are called the legs.
11. Ray QS is the angle bisector of angle PQR if S is in the interior of the angle and angle PQS = angle RQS.
13. A basic, undefined term of geometry that extends indefinitely that has no thickness or width; it is usually labeled by either a lower case script letter or two capital letters for points with a double arrow over the pair of letters.
14. A triangle with all sides congruent.
17. A triangle with at least two sides congruent. The congruent sides are called legs. The angles opposite the legs are base angles. The angle formed by two legs is the vertex angle. The third side is the base.
19. A segment, line, or plane that intersects a segment at is midpoint.
22. A line that intersects two or more lines in a plane at different points.
23. A triangle all of whose angles are acute angles.
24. The denial of a statement; the statement formed by negating both the hypothesis and conclusion.

1. A pair of adjacent angles whose noncommon sides are opposite rays.
2. A triangle with an obtuse angle.
3. Point M is the midpoint of segment PQ if M is between P and Q, and PM = MQ.
4. Lines in the same plane that do not intersect.
7. Two nonadjacent angles formed by two intersecting lines.
8. Two lines that intersect to form a right angle.
12. For an angle, the common endpoint of the two rays that form the angle. In a polygon, the endpoints of the sides is called a vertex. In a polyhedron, where three or more edges intersect. In a pyramid, the vertex that is not contained in the base of the pyramid. In a cone, the point opposite the circle.
14. A triangle with all angles congruent.
15. Part of a line that contains one endpoint but extends indefinitely in one direction; it is labeled by the endpoint and another point on the rat in that order.
16. Lines that do not intersect and are not in the same plane.
18. The statement formed by interchanging the hypothesis and conclusion of a conditional statement.
20. A triangle with no two sides congruent.
21. The statement formed by negating both the hypothesis and conclusion of the converse of a conditional statement.