Points Lines and Line Segments A Geometry presentation

Points, Lines, and Line Segments A Geometry presentation by Olivia Ingram

Points are places on a number line, often identified by a single dot “ • ” and are named an alphabetical letter. • A • B

Lines come in three forms: Ray • Line Segment • •

Measuring Points and Line Segments On a number line, you can easily measure the distance between two points. 0 1 A B • • 2 3 4 5 6 7 Two ways to solve: • Count the spaces between the points • Subtract the smallest number from the largest number 4 spaces between points = 4 6– 2=4 8

Measuring Points and Line Segments You may need to measure line segments whose points lie on both positive and negative numbers, which may throw you for a loop, but is just as simple. -4 -3 -2 A B • • -1 When counting, the negative and positive symbols make no difference =2 0 1 2 3 4 Do not solve this by subtraction. Ignoring the negative and positive symbols, add the points together: 1+1=2

Measuring Points and Line Segments Once you know how to measure the distance between points on a line segment, measuring more than two points on a line segment should be a piece of cake.

Answering Equations You should write the measurement of the distance between points using letters and symbols. 0 1 A B • • 2 3 4 = AB 5 6 7 8

Points, Lines, and Line Segments: Practice Problems A B • • -4 1 -3 2 -2 3 -1 Y • • 4 • -3 -2 1 X A -4 0 5 6 2 3 4 7 8 9 C • -1 0 • 1 2 3 4

Points, Lines, and Line Segments: Practice Problem Answers 1) AB = 5 2) XY = 2 3) AC = 5