Rotational Symmetry

Rotational symmetry is a characteristic of a shape or object that remains unchanged after a certain degree of rotation. In other words, if you can rotate a shape by a certain angle and it still looks the same, then the shape has rotational symmetry.

How to Identify Rotational Symmetry

To identify if a shape has rotational symmetry, follow these steps:

1. Draw the shape: Start by drawing the shape or object you want to analyze for rotational symmetry.
2. Identify the center: Find the point around which you will rotate the shape. This is usually the center of the shape or the point of symmetry.
3. Rotate the shape: Rotate the shape by different angles, such as 90°, 180°, or 360°. See if the shape looks the same after each rotation.
4. Determine the angles of rotation: Note the angles at which the shape looks unchanged. These angles represent the degrees of rotational symmetry of the shape.

Examples of Rotational Symmetry

Some common examples of shapes with rotational symmetry include:

• Circle: A circle has an infinite number of lines of symmetry. You can rotate it by any angle, and it will look the same.
• Equilateral Triangle: An equilateral triangle has rotational symmetry of 120°. You can rotate it by 120°, and it will look the same.
• Square: A square has rotational symmetry of 90° and 180°. You can rotate it by 90° or 180°, and it will look the same.

Study Guide

When studying rotational symmetry, make sure to focus on the following key points:

• Definition of rotational symmetry
• Identifying the center of rotation
• Determining the degrees of rotational symmetry for different shapes
• Practice rotating shapes to identify their rotational symmetry

It's also helpful to practice with different shapes and objects to gain a better understanding of rotational symmetry.

Remember to take note of the angles at which a shape looks unchanged, as these angles represent the degrees of rotational symmetry.

By following these steps and understanding the examples, you'll be well-prepared to identify and work with rotational symmetry in various shapes and objects.