Year 4-Points, Lines, Line Segments, Rays and Angles.pptx

POINTS, LINES,
LINE SEGMENTS,
RAYS AND ANGLES
Saturday 21 September 2024
1
Maths
Year 4
By: Jinky Dabon

2
A point is a location.
A point has no size.
We use a dot to mark a point.
We use a letter to name a point.
For example, when A is used to name
a point, it is shown as ·A and read as
Point A.

3
A line is a straight path that goes on
forever in both directions. A line has no
width.
LINES
The arrows show that
the line goes on
forever.

4
The line is called ‘line AB’ or ‘line BA’.
The symbol for ‘line AB’ is written as AB.
The symbol for ‘line BA’ is written as BA.
Point A and Point B are two points on the
line.
A B

5
(a)
E F
Exercise.
Write the name and symbol for each line.
(b)
Y Z
(c)
O P

6
Draw and name the line represented by
each symbol.
(a) CD
(b) GH
(c) WX
(d) JK

7
A line segment is a part of a line with two
end points.
LINE
SEGMENTS
line segment
end points

8
The name of the line segment is ‘line
segment AB’ or ‘line segment BA’.
The symbol for ‘line segment AB’ is
written as AB.
Point A and Point B are the end points of
a line segment.
A B
The symbol for ‘line segment BA’ is
written as BA.

9
How many line segments are there? Name
them.
H F
G
E
A B
C
D
E
Draw a picture that has 8 line segments, name
them and write the symbols for all the line
segments.

10
A ray is a line with one end point and an
arrow at the other end.
RAY
ray
end point
The arrow shows that
the line goes on
forever from here.

11
The name of the ray is ‘ray AB’.
Point A is the end point.
The symbol for ‘ray AB’ is written as AB.
There is an arrow after Point B.
A B

12
S R
The first letter in the name of a ray
must be the letter at the end point.
The arrowhead in the symbol must
always point to the right.
So, to write RS is wrong.
It should be written as RS.
From the symbol RS, we know that the
point R is the end point.

13
How would you name these rays?
U
V
S
T
Write the name and symbol of each ray.
D
C
J K
Draw and name the ray represented by each
symbol.
(a) TS (b) BC (c) LM

14
INTERSECTING
POINTS
An intersecting point is the point where two
lines, line segments or rays intersect or
cross each other.
D
E
F
G
H
Point H is the intersecting point
DE and FG intersect at
Point H.

15
R S
T
U
Point T is the intersecting point
RS and TU intersect at
Point T.

16
Name the intersecting points.
U
V
W
S
V
U
T
R
J
H
I
F
G

17
ANGLES
Two rays or two lines segments with a
common end point forms an angle.
The two rays or line segments are called
the sides of the angle.
The common end point is called the vertex
of the angle.

18
O
P Q
PO and PQ are two rays
that form an angle.
The common end point is
Point P.
So, Point P is the vertex
of the angle.
The angle is named ‘angle OPQ’ or ‘angle QPO’.
The symbol for ‘angle OPQ’ is written as OPQ.
The symbol for ‘angle QPO’ is written as QPO.

19
THE END

Year 4-Points, Lines, Line Segments, Rays and Angles.pptx

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Year 4-Points, Lines, Line Segments, Rays and Angles.pptx