SYMMETRY
Symmetry - part of a design that is repeated to make
a balanced pattern.
Artists use symmetry to make designs that are
pleasing to the eye.
Architects use symmetry to produce a sense of
balance in their buildings.
Symmetry is a feature of animals, plants, and
mechanical objects.
1. How might these three pictures earn the
label that they have symmetry?
2. What kinds of symmetry are represented
in each picture?
REFLECTION SYMMETRY
Have you ever made a simple
heart shape by folding and
cutting paper?
The heart is made by using
reflection symmetry.
Reflection symmetry is the SAME
thing as line symmetry.
If you place a mirror on the line of
symmetry you will see half of
the figure reflected in the mirror.
DO YOU NOTICE
LINE SYMMETRY IN NATURE?
DO YOU NOTICE
LINE SYMMETRY IN NATURE?
DETERMINE IF THE OBJECT HAS LINE
SYMMETRY. IF SO, DRAW ALL OF THE
LINES OF SYMMETRY.
3 Lines of
Symmetry
DETERMINE IF THE OBJECT HAS LINE
SYMMETRY. IF SO, DRAW ALL OF THE
LINES OF SYMMETRY.
4 lines of
symmetry
DETERMINE IF THE OBJECT HAS LINE
SYMMETRY. IF SO, DRAW ALL OF THE
LINES OF SYMMETRY.
No lines of symmetry.
Does this picture have line symmetry?
What kind of symmetry does it have?
Rotational Symmetry: A figure has
rotational symmetry when it can be
turned less than a full turn around its
center point in which it looks the same as
it does in its original position.
The Center of Rotation is a fixed point
about which you rotate the figure.
The Angle of Rotation is the smallest
angle through which you can turn the
figure so that it looks the same as it does
in the original position.
HOW DO YOU FIND THE ANGLE OF ROTATION?
1
1. Determine if the figure
has rotational symmetry.
2
2. Count how many partial
4
turns you can do to the
figure where the figure
lines up on itself.
3
For this shape divide 360˚ by 4.
3. Divide 360˚ by that
The answer is 90˚.
number.
The first rotation is 90˚, the
second is 180˚, the third is
270˚ and the fourth is 360˚.
Does this figure have Rotational Symmetry?
180˚
What is the first angle of rotation?
Does this figure have Rotational Symmetry?
30˚
What the first angle of rotation?
Does this figure have Rotational Symmetry?
No rotational symmetry
Does this figure have Rotational Symmetry?
120˚
What the first angle of rotation?