Line and Angle Relationships

Points, Lines, and Rays Sometimes it’s necessary to refer to a specific point in space Points have no size The only function of a point is to show position A, read “Point A” A

Points, Lines, and Rays If you draw two points on a sheet of paper, a line can be used to connect them Lines continue infinitely in both directions while a line segment has 2 endpoints A B AB, “line AB” AB, “line segment AB”

Points, Lines, and Rays A ray is the part of a line that extends without end in one direction A B C In AB, “ray AB,” A is the endpoint The second point that is used to name the ray can be any point other than the endpoint (You could also name it AC)

Points, Lines, and Rays Checkpoint Look at the line below: A B C Name a line segment Name a ray in two different ways What is the endpoint of ray BC? AB, AC, BA, BC, CB, and CA AB and AC or CB and CA Point B

Naming Angles Two different rays with the same endpoint form an angle The point they have in common is called the vertex of the angle The rays form the sides of the angle A B C

Naming Angles The angle above is made up of BA and BC Point B is the common endpoint or vertex When naming an angle we use the angle symbol

Naming Angles There are two ways to name an angle Using the three letters of the points that make up the two rays with the vertex as the middle letter ( ABC, or CBA) If only given the vertex then use just the letter of the vertex ( B) A B C

Naming Angles When more than one angle is formed by a vertex, you use three letters to name each angle Since A is the vertex of 3 different angles, each angle needs three letters to name it ( CAD, CAB, and BAD)

Naming Angles Checkpoint Look at the angles formed by the rays below: W X Y Z Name the vertex Name all three of the angles Point Y XYZ, XYW, and WYZ