Warm Up
1. The _________________ plane contains the x-axis and the y-axis.
2. Kira needs to buy a piece of pipe that is 40% longer than the 7-inch piece she already has. What length of pipe does Kira need?
3. Simplify .4. Evaluate for .
Lesson 1: Points, Lines, and PlanesGeometry
Vocabulary for Geometry
Definition: a statement that defines a mathematical object.
Undefined term: mathematical term that is not defined using other mathematical terms.
Points, lines, and planes are undefined terms that are the building blocks for defining other terms
Points and Lines
Point: names a location and has no size Represented by a dot Named with a capital letter
Line: a straight path that has no thickness and extends forever.
There are infinitely many points on a line Named with a lowercase letter or using any two points on the
lineC
A BDx
Collinear and Noncollinear
Collinear points: any set of points that lie on the same line
Noncollinear points: points that do not lie on the same line
C
A BDx
Planes
Plane: a flat surface that has no thickness and extends forever
Named with a capital letter or three noncollinear points that lie in the plane
Coplanar: lines or points that are in the same plane Noncoplanar: no plane contains all the lines or points Intersection: the point or set of points in which two
figures meet Two lines intersect at a point Two planes intersect in a line
Example
Name the line below in two different ways.Name all the points.
Z
X WYm
Example
Use the diagram to answer each question.a. What is the intersection of and ?b. What is the intersection of and plane š¯’²? c. What is the intersection of and plane š¯’²?
š¯’²N
M
P
K
J
Example
Can two points be noncollinear?
Example
How many points can a line contain?
How many points can a plane contain?
Example
John used two points to name a plane. What mistake did John make in naming the plane?
Homework
1st and 2nd hour: Lesson 1 #1-30
3rd hour: Lesson 1 #1-30 even