6th Grade Math Textbook, Fundamentals

 &KDSWHU

9-1

Points, Lines, and Planes

Objective To identify collinear and noncollinear points, lines,

line segments, rays, angles, parallel lines, intersecting lines,

perpendicular lines, and skew lines • To read and write symbols

for geometric figures • To identify parallel, intersecting, and

perpendicular planes

Many artists from all over the world incorporate geometric figures into
their paintings, pots, textiles, and tapestries.

Points, lines, and planes are the most basic geometric figures.

Figure Definition Read/Write

• A A is an exact location in space. Although
  represented by a dot, a point has no size. It is named
  by a letter.

point point A



B

A

collinear points

A is a continuous set of points in a straight path. It

extends without end in both directions. It can be named

by any two points on the line. It is sometimes named by

a lower-case letter.

If a straight line can be drawn through a set of points,

the points are. If no one line can be drawn

through all the points, the points are noncollinear.

collinear

line line ABor

line BA

AB orBA

line 

E F

two endpoints A is a part of a line and has two endpoints.

Line segment EFconsists of endpoints Eand F and all

the points between Eand F. A line segment is named by

its endpoints.

line segment line segment

EF orFE

EFor FE

B C

one endpoint A is part of a line that has one endpoint. It continues

infinitely in the opposite direction. It is named by its

endpoint and any other point on the ray.

ray rayBC

BC

C

1

A

B

An is a figure formed by two rays with a common

endpoint, the (plural: vertices) of the angle. The

rays form the sides of the angle. An angle can be named

in several different ways: You can use the letters of

three points that make the angle, one point on each ray

with the vertex letter as the middle letter; just the letter

of the vertex; or just a number.

angle

vertex

angleABC

ABC

angleCBA

CBA

angle B

B

angle 1

 1

Z

Y

X

Points X, Y, and Z

are coplanar.

A is a flat, two-dimensional surface that extends

infinitely in all directions. It is named by at least three

points in the plane that are notall collinear. Points and

lines that lie in the same plane are called coplanar.

plane plane XYZ