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.