Geometry | Term 2 Chapter 1 | 4th Maths - Introduction of symmetry | 4th Maths : Term 2 Unit 1 : Geometry
Chapter: 4th Maths : Term 2 Unit 1 : Geometry
Introduction of symmetry
Introduction of symmetry
In our day to day activity we see
many leaves of plants, blades, wings of butterflies etc.
The figures which can be divided
into two parts of equal shape and size are called symmetrical figures.
EXAMPLE
The two halves of the figures are
the mirror images of each other.
EXAMPLE
Activity
• Draw the mirror symmetry using the
other half.
Symmetry
The line which divides a figure into two equal halves is called the line
of symmetry.
Symmetry in Geometrical shapes
A
square has four lines of symmetry
A rectangle has two lines
of symmetry.
A
circle has infinite
lines of symmetry
An
equilateral triangle has three lines
of symmetry
Activity
Find out the symmetrical figure
and colour it:
1. Able
to explore intuitively the reflections through mirror ink blots, paper cutting
and paper folding:
Activity
• Take a piece of
paper. Fold it exactly into half. Now take the folded edge and fold it into
itself. Cut from one folded edge to the other folded edge. Open the paper and
get a symmetrical figure.
Activity
Let us understand the concept of
symmetry by paper folding:
• Take a white sheet
of paper and fold it once such that it is divided into two equal parts.
• Mark any two points say A and B on the folded line. As
shown in figure.
• Draw a closed figure on the folded paper beginning at a
point and ending at the other point.
• Cut the closed figure along the dotted lines marked.
• Unfold the paper. The half shapes on the either side of the
line of fold AB are exactly the same.
• The line of the fold is the line of symmetry.
2. Able to draw top
view, front view and side view of simple objects.
3. To observe from
the surroundings and from day to day life situations and identify symmetrical
objects.
Activity
Check whether the following pictures are
symmetrical or not symmetrical
4. Collects record
symmetrical objects whenever / wherever they see.
Activity
• Observe the objects around you at home. List the name and shape of the
objects. Above these objects which can be called as symmetrical.
Name : Shape
1. Clock - Circle
2. Television - Rectangle
3. Funnel - Cone
4. Books - Rectangle
5. Match boxes - Rectangle
6. Carom board - Square
7. Orange - Sphere
5. To draw such
symmetrical objects and naming the same.
Related Topics