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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. - PowerPoint PPT Presentation
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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
•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
Rotation Symmetry
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˚