1. Geometry Vocabulary

2. What is Geometry? Geometry is the study of shapes
They studied Geometry in Ancient Mesopotamia & Ancient Egypt
Geometry is important in the art and construction fields

3. POINT A POINT is an exact location on a graph, shape or in “space”.
We name the point with a letter. A ●

4. ENDPOINT An ENDPOINT is a point at the end of a ray or line segment.

5. Line vs Line Segment
A LINE is a collection of points on a straight path. Extending in both directions and never, never, never ends.
Lines that end are called LINE SEGMENTS.
A AB B

6. RAY
A RAY is part of a line, but it has one endpoint and the other end keeps going. A ●
Endpoint

7. MIND POINT
It Is a point located in the exact center of a line segment. A M B M is the midpoint of AB

8. CONGRUENT CONGRUENT means the “same”.
CONGRUENT LINE SEGMENTS means two line segments are the same.
A B
C D ● ●
AB = CD ● ●

9. Congruent Symbols
What can be said about line segments AB and CD A B C D

10. Examples
2 5 4 A B C D E What is the length of line segment CD?

11. Perpendicular lines
Two lines that meet at a 90 degree angle

12. Parallel
Two lines that never meet

13. Intersecting
Lines that just cross

14. Bisector
A line that cuts another line in half( two equal pieces) at a 90 degree angle.
A B
Bisector

15. Angle Bisector A ray that cuts an angle in half ( two equal pieces). B

16. VERTEX A VERTEX is a fancy name for “angle”
Two rays or lines that have the same endpoint make a VERTEX/angle
VERTEX/angles are measured in “degrees”
When two lines cross, they make vertex/angles
The Corners of a square are its vertex/angles

17. Measure
Symbol M
Examples:
M AB
M ABC
M DEF

18. PROTRACTOR
We use a PROTRACTOR to measure vertex/angles in degrees

19. Degree Basic unit of measurement for an angle. Symbol ° Example:
M ABC = 90°

20. Angles
When 2 edges or sides meet. A Vertex ( common part).

21. ANGLES
When you “name” an angle. The vertex/angle “letter/number” goes in the center of the label B A C
If I wanted to know the measurement of Angle A…I would ask:” What is the measurement for BAC?” (Notice A is in the center)

22. 4 TYPES OF ANGLES RIGHT ANGLES measure exactly 90 °
The “square” symbol means 90’

23. 4 TYPES OF ANGLES
ACUTE ANGLES are less than 90°

24. 4 TYPES OF ANGLES
OBTUES ANGLES are greater than 90 ° but less than 180 °

25. 4 TYPES OF ANGLES
STRAIGHT ANGLE is exactly 180 °