What’s on the Menu Today?

Daily Warm Up

Turn in and go over homework questions

1.2 Notes on Basic Geometric Terms

Basic Definitions Work Sheet
Warm It Up
#1
Using what you learned about the Three Steps to
Reason, make a conjecture about the first 100
positive even integers.
Identifying Geometric Terms in Real Life
SECTION 1.2: BASIC
GEOMETRIC TERMS
Definition: Point

A point has no dimension and is usually represented
by a small dot.
Point A
.
A
Definition: Line


A line extends without end in two directions. It is usually
represented by a straight line with two arrowheads
(symbolized by AB)
Collinear Points: two points that lie on the same line.

Example: A and B are collinear points
Definition: Line Segment

A Line Segment is the part of a line ending
at two specific points and all the points
between the two endpoints.
A
B
(Notice there are no arrows at the end)
Definition: Ray & Initial Point

The ray AB (symbolized by AB) consists of the initial
point A and all points on AB that lie on the same
side of A as point B.
IMPORTANT: the first letter must indicate the
starting point of the ray.
Definition: Opposite Rays

Opposite Rays share a common initial point, but
point opposite directions. If C is between A and B,
then CA and CB are opposite rays.
A
C
B
Any two opposite rays are collinear.
Recap
Line
Segment
Ray
Opposite Ray
.
A plane extends in two
dimensions. It is usually
represented by a shape that
looks like a table or a wall,
however you must imagine that
the plane extends without end
Definition: Coplanar Points

Coplanar points are points that lie on the same
plane.
.A
.C


.B
M
Call it: Plane M or plane ABC
Note: points A,B,C are coplanar points.
Definition: Intersect


Geometric figures are said to intersect if they have
one or more points in common.
The intersection of the figures is the set of points
the figures have in common.
Your Turn
EX: Sketch a line that intersects a plane at one point.
Solution:
 Draw
a plane and a line
 Emphasize the point
where they meet
 Dashes show where
the line is hidden
by the plane.
Your Turn
Ex: Sketch two planes whose intersections form a line.
Solution:
 Draw
two planes
 Emphasize the line
where they meet.
 Dashes indicate that one
plane is hidden by the other.
Homework
P. 13 # 3 - 67 Odd, 73 - 75