Warm-ups
P. 869 1-5 no calculators These problems are due in 3 min.
Date
Sec 1-1
Concept: Identify Points, Lines and Planes
Objectives:
Given basic concepts in Geometry, name and sketch geometric figures
3-Undefined Terms in Geometry
Point Line Plane
Undefined. It has no dimension. It is usually represented by a small dot
Point
ALabel with Capital Letters
Line
Undefined Extends in one dimension. Usually represented by a straight line with arrows on the ends.
A Bl
Labels: AB BA l
Plane:
undefined Extends in two dimensions. Usually represented by a shape that looks like a table top.
A
B
C
M
Plane M or plane ABC
Key Terms – you probably already know some of these… Coplanar and Noncoplanar Collinear and Noncollinear Ray Segment Opposite ray Intersect
Collinear: points that lie on the same line
P I G S
Points P, I, G, and S are collinear
Non-Collinear: Points that do not lie on the same line
D
O
G
Points D, O and G are noncollinear
Coplanar: Points that lie in the same plane
Points M, A, T, H, S are coplanar
HT
S
G
M A
Non -Coplanar: Points that do not lie in the same plane
Points G, S and H are non- coplanar
A
HT
S
G
M
Line Segment: Part of a line that consists of 2 endpoints
AB or BA
A B
Ray: Part of a line that consists of a point called the initial point and all points on the line that extend in one direction.
A
B
A is the initial point
AB
Opposite Rays: If C is between A and B, then CA and CB are opposite rays
AC B
Intersect: To have one or more points in common
Intersection: The set of points that two or more geometric figures have in common
C
L
PN M
O
1. Name 3 coplanar points
2. Name 3 collinear points
3. Name 3 non-collinear points
4. Name a line segment in two different ways
5. Name a ray
Example 1:
C
L
PN M
O
6. Name a line in 2 ways
7. Name a point
8. Name the plane in two ways
9. What is the intersection of LO and plane C
Example 1: Cont.
Example 2: Sketch the figure described
A. A line and a plane that do not intersect
B. 2 planes that do not intersect and a line that intersects each plane in 1 point
Example 3: Determine if the point lies on the line
A. Y = x-4 A(5,1)
1 = 5-4
1=1
YES, it lies on the line
B. Y = 2x + 3 A(7, 16)
16 = 2(7) + 3
16 ≠ 17
NO, It doesn’t lie on the line
Example 4: Graph the inequality on the number line. Tell whether the graph is a segment, a ray or rays, a point or a line
X>2 or x<5
0 2 5
Line
Example 5: What kind of Geometric Intersection does the photograph suggest?
The intersection of 2 lines
The intersection of a line and a plane
Today’s Work:
In Class:
Homework: