The document discusses basic concepts in geometry including points, lines, planes, and their relationships. It defines a point as having no size or shape, a line as connecting two or more points and extending indefinitely in both directions, and a plane as a flat two-dimensional surface containing points and lines. The document provides examples of naming points, lines, and planes and identifies collinear points that lie on the same line and coplanar points that lie on the same plane. It includes practice problems asking students to name, draw, and identify various geometric concepts.
3. OBJECTIVES
By this end of the presentation you will be able to:
Identify and model points, lines, and planes.
Identify collinear and coplanar points.
Identify non collinear and non coplanar points.
5. POINTS
A point indicates a position or location in space.
Point has no size and shape = no dimension.
Point is represented by a small dot.
points are named using capital letters.
Example: .A or “Point A”
.B .C
.D
6. Line
Line is two or more points which are
connected and are endless in both directions.
It never ends.
It is represented by a straight line with two
arrowheads to indicate that the line extends
without end in two directions.
The symbol for a line
7. NAMING A LINE
Line is named using any two points on a line or with a
lower case letter.
a)Two points on a line:
AB, AC , BA, BC , etc...
A B C
b) Single lowercase letter
m
Example: name the line below.
m .
A
.
B
Ans. Line m or AB or BA
8. Plane
• Plane is a flat two dimensional surface which contains points,
lines, segments. plane figures are closed
• It is represented by a shape that looks like a tablecloth or wall.
Example of Planes: walls, desk tops, floors, and paper etc
wall
Planes are everywhere around us.
Floor Desk top
paper
9. Naming a Plane
Planes are named using three points on a plane or cursive capital
letters.
a) Three points on the plane:
B •
Plane ABC A • C •
b) Single cursive uppercase letter:
R
Plane R
Example: name the plane below.
R
A •
B •
C • Ans. Plane ABC Or Plane R
10. Naming collinear and coplanar points
Collinear points are two or three points on the
same line. Collinear points A, B,C and points D, B,E
Fig. 1
Non collinear:
Any three points combination that are
not in the same line. E.g. points ABE
E
Fig.2
A B C
Coplanar points are four or more point to point on the same plane.
D
Coplanar points: ABCD .E
Non-Coplanar point:
.
.
. .
11. PRACTICE
1.Draw a noncollinear point, J K, L.
2.Draw
JK = KL = LJ =
3. Draw plane S.
4. Draw a collinear point, A, B, C.
5. Draw point Z.
12. PRACTICE
Name a point that is collinear with the given points.
1. F and H
2. G and K Ans.
3. K and L 1.K
4. M and J 2. N
G
5. J and N 3.M
4. F
6. K and H L
5. L
7. H and G 6. F
8. J and F 7.J
8.M
14. PRACTICE
Decide whether the statement is true (T) or false (F)
1. Points A,B and C are collinear.
2. Points A,B and C are coplanar.
3.Point F lies on DE.
4. DE lies on plane DEF.
5. BD and DE intersect.
6. BD is the intersection of plane ABC
and plane DEF.
Ans.
1. F 2. T 3. F 4. T 5. T 6. T
15. PRACTICE
Name a point that is coplanar with the given points
1. A, B, and C
2. D, C, and F
3. G, A, and D
4. E, F, and G
5. A, B and H
Ans.
1. D 2. G 3. H 4. H 5. E
16. PRACTICE
Name all the points that are not coplanar with the given points.
1.N, K and L
2. S, P and M
3. P, Q and N
4. R,S and L
5. P, Q, and R
Ans. 1.) R, S, P, Q 2) K,N,Q,R 3) S,R,L,K 4) M, N, P, Q 5. K,L,M,N
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