1-1: Point Lines and Planes
Part 1
Today’s Objective:
By the end of the class, I will be able to identify basic geometric vocabulary using words, symbols, and sketches.
TERM DESCRIPTION SKETCH NAME IT
POINT
An exact location in space with
indefinite shape and size.
TERM DESCRIPTION SKETCH NAME IT
LINE
An object with no thickness that
extends infinitely in TWO directions.
TERM DESCRIPTION SKETCH NAME IT
LINESEGMENT
A “piece” of a line consisting of 2
endpoints and all points in between.
TERM DESCRIPTION SKETCH NAME IT
RAY
A “piece” of a line consisting of 1
endpoint and all points in between.
TERM DESCRIPTION SKETCH NAME IT
OPPOSITERAYS
Two rays sharing the same endpoint
and continuing infinitely in
opposite directions.
TERM DESCRIPTION SKETCH NAME IT
PLANEA flat surface that extends infinitely in all directions.
TERM DESCRIPTION SKETCH NAME IT
COLLINEARPoints that lie on
the same line.
TERM DESCRIPTION SKETCH NAME IT
NON-COLLINEAR
Points that DO NOT lie on the same
line.
TERM DESCRIPTION SKETCH NAME IT
COPLANARPoints that lie on the same plane.
TERM DESCRIPTION SKETCH NAME IT
NON-COPLANAR
Points that DO NOT lie on the same
plane.
• Using your straight edge (ruler), draw a line segment that is 10 centemeters long.
• Label one end point J, and the other endpoint L.
• Put a point, K, anywhere on JL.• Measure the distance from J to K, round
it to the nearest half centimeter. • Measure the distance from K to L, round
it to the nearest half centimeter.
JK KL
Segment Addition Segment Addition PostulatePostulate
Points A, B, and C are collinear.
AB + BC = AC
Example 1Example 1If B is between A and C and AB = 4 and BC = 5, find AC.
Example 2Example 2If AB = x, BC = x + 6, AC = 24,
find AB and BC.
Example 3Example 3Find LM if L is between N and M,
NL = 6x – 5, LM = 2x + 3 and NM = 30.