Key Concepts of
Geometry
Introduction to undefined terms
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;
Akala ko tayo pero hindi…
Hugot pa more…
Anong point ng mga linyang sinambit mo
kung plane friends lang naman tayo.
Sana intersecting lines na lang tayo,
para magmeet tayo sa isang point.
#WALANGKAYO
Feelings in all levels are suspended according to
your pag-asa.
Ang crush parang math problem,
pag di mo makuha titigan mo na lang.
Di kita nakita sa party kanina, ano
suot mo?
Forever. Kaya di mo ko mahanap
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
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
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
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?
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?
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?
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?
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?
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

Key concepts of geometry

  • 1.
  • 2.
  • 3.
    The learner areexpected 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 tayopero hindi…
  • 5.
  • 6.
    Anong point ngmga linyang sinambit mo kung plane friends lang naman tayo.
  • 7.
    Sana intersecting linesna lang tayo, para magmeet tayo sa isang point.
  • 8.
    #WALANGKAYO Feelings in alllevels are suspended according to your pag-asa.
  • 9.
    Ang crush parangmath problem, pag di mo makuha titigan mo na lang.
  • 10.
    Di kita nakitasa party kanina, ano suot mo? Forever. Kaya di mo ko mahanap
  • 15.
    Term Illustration DescriptionNotation 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 DescriptionNotation 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 DescriptionNotation 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 pointsA, 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 pointsA, 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 pointsA, 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 pointsA, 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 pointsA, 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 pointsA, 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