# Points, lines, line segments, and rays

### Points, lines, line segments, and rays

In this lesson, we will learn:

Notes:

• Points, Lines, Line Segments and Rays are basic figures in math that can be used to construct more complicated figures (i.e. angles, shapes, parallel/perpendicular lines, etc.)

• A point is a dot with position but no size nor shape (undefined) $\,$
• There are an infinite number of points in figures (i.e. you can draw many points between endpoints in a line segment) $\,$
• The proper notation of a point is just to write the named letter (ex. point $A$)

• A line has no beginning/end; an ongoing straight path of points
• The arrows on both sides mean that it can extend infinitely in that direction
• The proper notation of a line is to write the letters of two points in the figure and draw a double-sided arrow above the letters (ex. line $\overleftrightarrow{AB}$)

• A line segment is a part of a line with two finite endpoints
• A line has arrows on both ends whereas the line segment has endpoints on both ends; the line continues forever, where the line segment ends where it is drawn
• The proper notation of a line segment is to write the letters of the two endpoints and draw a bar above the letters (ex. line segment $\overline{AB}$)

• A ray starts at one endpoint and extends in one direction
• One end of the ray has a point, whereas the other end of the ray has an arrow
• The proper notation of a ray is to write the letters of two points in the figure (starting with the letter of the endpoint) and draw a one-sided arrow above the letters (ex. ray $\overrightarrow{AB}$ )

#### Lessons

• Introduction
Introduction to Points, Lines, Line Segments and Rays:
a)
Introduction to basic figures and points

b)
What are lines?

c)
What are line segments?

d)
What are rays?

e)
Review of points, lines, line segments and rays

• 1.
Identifying lines, line segments, and rays
Name the figure that is made by points $A$ and $B$ as either: a line, a line segment, or a ray.
a)

b)

c)

d)

e)

• 2.
Proper notation for lines, line segments and rays
Use proper notation (with letters and symbols) to name the figure
a)

b)

c)

• 3.
Drawing lines, line segments and rays
Draw the figure:
a)
ray $\overrightarrow{MN}$

b)
line segment $\overline{QR}$

c)
line $\overleftrightarrow{GH}$

• 4.
Combinations of lines, line segments and rays
Name all the lines, line segments, and/or rays in the picture. Use proper notation.
a)

b)

c)

• 5.
Intersecting lines, line segments and rays
Connect the dots to draw the figures as indicated. Will the figure intersect? Yes or No.
a)
$\overrightarrow{XW}$ and $\overleftrightarrow{YZ}$

b)
$\overline{AB}$ and $\overrightarrow{DC}$

c)
$\overline{NO}$ and $\overrightarrow{PQ}$

d)
$\overline{RS}$ and $\overleftrightarrow{TU}$