Describing Rotations
Rotational Symmetry in Nature
Rotational Symmetry in the world…
Rotation Symmetry
• The compass star has rotation
symmetry.
• You can turn it around its
center point to a position in
which it looks identical to the
original figure.
Rotation Symmetry
• How many degrees will I need
to rotate point A so it will line
up on point C?
• 90˚ clockwise
• How many degrees will I need
to rotate point A so it will line
up on point E?
• 180˚ clockwise
Rotation Symmetry
• How many degrees will I need
to rotate point A so it will line
up on point G?
• 270˚ clockwise
• How many degrees will I need
to rotate point A so it will line
up on point A?
• 360˚ clockwise
Rotational Symmetry Rules
• A shape has rotational symmetry if it fits onto
itself two or more times in one complete
turn.
• First, determine how many times a figure can
land on itself including the full turn.
• Then divide 360˚ by that number to get the
first rotational degree.
• For example, the figure above can be turned and
land on itself 4 times.
• 360˚ ÷ 4 = 90˚.
• The rotational degrees are 90˚, 180˚, 270˚ and
360˚.
Determine if the shape has rotational
symmetry. If it does, find all of its
rotational symmetries.
Yes = 180˚, 360˚
Determine if the shape has rotational
symmetry. If it does, find all of its
rotational symmetries.
Yes = 120˚,
240˚ & 360˚
Determine if the shape has rotational
symmetry. If it does, find all of its
rotational symmetries.
No rotational symmetry
Determine if the shape has rotational
symmetry. If it does, find all of its
rotational symmetries.
Yes = 60˚,
120˚, 180˚,
240˚ 300˚, &
360˚