Undefined terms in Geometry

1. Key Concepts of
Geometry

2. Introduction to undefined terms

3. The learner are expected to:
 describe the undefined terms;
 give examples of objects that maybe used
to represent the undefined terms;
 name the identified point(s), line(s) and
plane(s) in a given figure;

4. Akala ko tayo pero hindi…

5. Hugot pa more…

6. Anong point ng mga linyang sinambit mo
kung plane friends lang naman tayo.

7. Sana intersecting lines na lang tayo,
para magmeet tayo sa isang point.

8. #WALANGKAYO
Feelings in all levels are suspended according to
your pag-asa.

9. Ang crush parang math problem,
pag di mo makuha titigan mo na lang.

10. Di kita nakita sa party kanina, ano
suot mo?
Forever. Kaya di mo ko mahanap

15. Term Illustration Description Notation
Point A
A point suggests
an exact
location in
space.
It has no
dimension.
We use a capital
letter to name a
point.
point A

16. Term Illustration Description Notation
Line
A line is a set of
points arranged in a
row.
It is extended
endlessly in both
directions.
It is a one-
dimensional figure.
Two points
determine a line.
That is, two distinct
points are contained
by exactly one line.
We use a lower case
letter or any two
points on the line to
name the line.
RV
VR or m
m
R V

17. Term Illustration Description Notation
Plane
A plane is a set of
points in an
endless flat
surface.
The following
determine a plane:
(a) three non-
collinear points; (b)
two intersecting
lines;
(c) two parallel
lines; or (d) a line
and a point not on
the line.
Plane PQR or
PQR

18. Given: The points A, B, C, D, E, F, G, H
are corners of a box shown below:
 How many lines are possible which can
be formed by these points?
 What are the lines that contain the
point A?
 Identify the different planes which can
be formed by these points.
 What are the planes that contain line
DC?
 What are the planes that intersect at
line BF?

19. Given: The points A, B, C, D, E, F, G, H
are corners of a box shown below:
 How many lines are possible which can
be formed by these points? 28
 What are the lines that contain the
point A?
 Identify the different planes which can
be formed by these points.
 What are the planes that contain line
DC?
 What are the planes that intersect at
line BF?

20. Given: The points A, B, C, D, E, F, G, H
are corners of a box shown below:
 How many lines are possible which can
be formed by these points? 28
 What are the lines that contain the
point A? AB, AC, AD, AE, AF, AG, AH
 Identify the different planes which can
be formed by these points.
 What are the planes that contain line
DC?
 What are the planes that intersect at
line BF?

21. Given: The points A, B, C, D, E, F, G, H
are corners of a box shown below:
 How many lines are possible which can be
formed by these points? 28
 What are the lines that contain the point A?
AB, AC, AD, AE, AF, AG, AH
 Identify the different planes which can be
formed by these points. ABC, ADE, ABE, CDH,
BCG, EFG, ABG, BCE, CDE, ADF, ACF, ACH,
BDE, BDG, BEG, DEG, AFH, BFH, ACE, BDF
 What are the planes that contain line DC?
 What are the planes that intersect at line
BF?

22. Given: The points A, B, C, D, E, F, G, H
are corners of a box shown below:
 How many lines are possible which can be
formed by these points? 28
 What are the lines that contain the point A?
AB, AC, AD, AE, AF, AG, AH
 Identify the different planes which can be
formed by these points. ABC, ADE, ABE, CDH,
BCG, EFG, ABG, BCE, CDE, ADF, ACF, ACH,
BDE, BDG, BEG, DEG, AFH, BFH, ACE, BDF
 What are the planes that contain line DC?
ABC, CDH, CDE
 What are the planes that intersect at line
BF?

23. Given: The points A, B, C, D, E, F, G, H
are corners of a box shown below:
 How many lines are possible which can be
formed by these points? 28
 What are the lines that contain the point A?
AB, AC, AD, AE, AF, AG, AH
 Identify the different planes which can be
formed by these points. ABC, ADE, ABE, CDH,
BCG, EFG, ABG, BCE, CDE, ADF, ACF, ACH,
BDE, BDG, BEG, DEG, AFH, BFH, ACE, BDF
 What are the planes that contain line DC?
ABC, CDH, CDE
 What are the planes that intersect at line
BF? ABF, BCF, BDF