1. A Game and Some Geometry
Section 1-1
A Game and Some Geometry
EQUIDISTANT
equally distant

2. Points, Lines, and Planes
Section 1-2
Points, Lines, and Planes

3. 3 Undefined terms in Geometry: 1. 2. 3.
Point
Line
Plane

4. Point
- represented by a dot
- a location
- no length
- no width
- no thickness
- named by a capital letter

5. - infinite set of points that extends in two directions - no width
LINE
𝐴𝐵 ,
𝐵𝐴 ,
line l
𝐴𝐶 ,
𝐶𝐴 ,
𝐵𝐶 , 𝐶𝐵 • C
- infinite set of points that extends in two directions
- no width
- no thickness
- no definite length (cannot be measured)
- named by two points on the line or by a lowercase letter

6. COLLINEAR POINTS – NONCOLLINEAR POINTS –
points all in one line
points A, C, D, and B are collinear
points not on the
same line
points A, C, D, B and E are noncollinear

7. PLANE
- infinite set of points that creates a flat surface and extends without ending
- no edges
- no specific length (cannot be measured)
- no specific thickness
- named by a capital letter or the letters around
plane M or plane XYZ
* Any 3 points make a plane, 4 points to be noncoplanar

8. COPLANAR POINTS – NONCOPLANAR POINTS –
points all in one plane
points A, B, and C are coplanar
points not on the
same plane
points A, B, C, and D are noncoplanar

9. 2 3

10. (4 points not all on one plane)
SPACE – INTERSECTION –
set of all points
(4 points not all on one plane) •D •A • C • B
set of points that lie in two or more figures

11. Line l and line m intersect at point A.
The intersection of 2 lines is a ______________. The intersection of 2 planes is a _____________. l m • A
Line l and line m intersect at point A.
line
Plane M and plane N intersect at 𝑋𝑌 .

12. Line l and plane M intersect at point Q.
The intersection of a plane and a line not on that plane is a ___________.
point l M
• Q
Line l and plane M intersect at point Q.

13. Examples:
Classify each statement as true or false.
1. 𝑃𝐹 ends at P.
2. Point S is on an infinite number of lines.
3. A plane has no thickness.
4. Collinear points are coplanar.
False
True
True
True

14. 5. Planes have edges. 6. Two planes intersect in a line segment. 7
5. Planes have edges. 6. Two planes intersect in a line segment. 7. Two intersecting lines meet in exactly one point. 8. Points have no size. 9. Line XY can be denoted as 𝑋𝑌 or 𝑌𝑋 .
False
False
True
True
True

15. Use the diagram below to classify each statement as true or false.
10. P is in M.
11. b is in M.
12. 𝑌𝑋 contains P.
False
True
False

16. 13. A in on b.
14. A and P are in M.
15. N contains P.
True
False
True

17. HOMEWORK: page 7 #1-20 all (CE)