Symmetry
A geometrical figure is said to be symmetric about a
line if on folding the figure about this line the two halves of the figure
exactly coincide.
Line of Symmetry
A line of symmetry divides a figure in equal halves.
Figures can have more than one line of symmetry.
Look at the square below. How many lines of symmetry
can you count?
Does a rectangle have as many lines of symmetry as a
square? Remember that a line of symmetry splits a figure in 2 halves so that
each half exactly coincides the other. Notice that the rectangle has two lines
of symmetry.
A rectangle cannot have a diagonal line of symmetry
like a square because the sides are not of the same length. If you fold this
rectangle diagonally so that Corner A meets Corner D, the sides would not match. Try it with a
piece of paper!
You can draw lines of symmetry on many different
figures. Look at the lines of symmetry on the figures below. Notice how
different types of figures can have different numbers of lines of symmetry.
Some symmetrical shapes have one line of symmetry, some have two
and some have more than two, as shown below:
1.
Examples of the
shapes having one line of symmetry:
3. Examples
of the shapes having three lines of symmetry:
4.
Examples of the
shapes having four lines of symmetry:
5.
Examples of the
shapes having many lines of symmetry:
6.
Examples of the
shapes having no line of symmetry:
