WJEC MATHEMATICS
INTERMEDIATE
SHAPE AND AREA
SYMMETRY
1
Contents
Lines of Symmetry
Symmetry of Common Shapes
Rotational Symmetry
Credits
WJEC Question bank
http://www.wjec.co.uk/question-bank/question-search.html
2
Lines of Symmetry
A line of symmetry is a line, such that it divides a shape in two, and
the line acts as a mirror line (or a fold line).
Example
Consider the letter 'A' with the following mirror (fold) lines.
If each of these letters are the folded along the fold lines, only one of
them remains the same.
So, the line going vertically down the centre of the 'A' is a line of
symmetry.
Exercise G9
Draw the lines of symmetry on the following letters
B T MNS
3
Symmetry of Common Shapes
Knowing these will be beneficial in an exam.
IMPORTANT!
A circle has a
infinite number
of lines of
symmetry
A rectangle does NOT
have a diagonal line of
symmetry!
4
X
Exam Questions G19
1.
2.
3.
5
Rotational Symmetry
The order of rotational symmetry of a shape is the number of times a
shape will fit onto itself in a complete 360o turn.
Examples
This shape only fits
over itself once in a
360o turn (That is,
after 360o) so it has
rotational symmetry
ORDER 1
This shape fits over
itself twice in a 360o
turn (That is, after
180o and 360o) so it
has rotational
symmetry ORDER 2
Similarly, this shape
has rotational
symmetry ORDER 3
And this shape has
rotational symmetry
ORDER 4
6
Exercise G10
State the order of rotational symmetry of the following shapes
2.
1.
4.
6.
5.
7.
3.
8.
9.
7
Exam Question G20
1.
2.
3.
8
4.
5.
9