Lesson 2: 1-2: Line Segments

When are two segments congruent?
How is the distance determined between two points on a number line?

Line segment
Betweenness of points
Between
Congruent
Rigid transformation
Congruent segments
Construction
Distance
Irrational number

C.CO.1
Know precise definitions of angle, circle, perpendicular line, parallel line, and and line segment, based on the undefined notions of point, line, distance along a line, and distance around a circular arc.
G.CO.2
Make formal geometric constructions with a variety of tools and methods (compass and straightedge, string, reflective devices, paper folding, dynamic geometric software).

A line cannot be measured because it extends infinitely in each direction. A line segment, however, has two endpoints and can be measured. The distance between the endpoints of a line segment on a number line is the absolute value of their difference.

Indianapolis, Indiana is between St. Louis, Missouri and Columbus, Ohio. If you drive on Interstate 70 from St. Louis to Columbus, you will pass through Indianapolis.

Students approaching grade level can be given practice problems in small groups to work with other students or directly with the teacher.
Students beyond grade level can make deeper connections in the following way: students can physically participate in techniques of measuring, accuracy, and the betweenness of points by grouping in threes, standing in designated spots, and using a yardstick to measure distances between them, add distances together, and find unknown distances.

Formative Assessment

Textbook in class

Access online textbook and resources through class link.