# © T Madas. We can extend the idea of rotational symmetry in 3 dimensions:

## Presentation on theme: "© T Madas. We can extend the idea of rotational symmetry in 3 dimensions:"— Presentation transcript:

We can extend the idea of rotational symmetry in 3 dimensions:

We can extend the idea of rotational symmetry in 3 dimensions: We say that this solid has rotational symmetry, about the line shown. This line is sometimes called axis of symmetry The order of this rotational symmetry is 4, about the line shown

© T Madas In general in 3D space: A solid has rotational symmetry if the transformation of rotation about one or more axes, leave the solid unchanged order 4 order 2 If a solid has two or more axes of rotational symmetry which meet at a point, then the solid is said to have point symmetry.

© T Madas In general in 3D space: A solid has rotational symmetry if the transformation of rotation about one or more axes, leave the solid unchanged infinite order infinite axes with order 2 infinite axes infinite order If a solid has two or more axes of rotational symmetry which meet at a point, then the solid is said to have point symmetry.

© T Madas Is it possible to have rotational symmetry in 3D space without a single axes of rotational symmetry? No axes of rotational symmetry?

© T Madas Is it possible to have rotational symmetry in 3D space without a single axes of rotational symmetry? No axes of rotational symmetry?

Look at the following shapes Label them using the following code: R = it has rotational symmetry N = no rotational symmetry 0 = no plane of symmetry 1 = 1 plane of symmetry 2 = 2 planes of symmetry 3 = 3 planes of symmetry 4 = 4 planes of symmetry etc E.g. N2: no rotational symmetry, 2 planes of symmetry

Look at the following shapes Label them using the following code: R = it has rotational symmetry N = no rotational symmetry 0 = no plane of symmetry 1 = 1 plane of symmetry 2 = 2 planes of symmetry 3 = 3 planes of symmetry 4 = 4 planes of symmetry etc E.g. N2: no rotational symmetry, 2 planes of symmetry

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