Rotational Symmetry

Rotational symmetry is a property of a shape or an object that allows it to be rotated by a certain angle and still look the same. The angle of rotation at which the shape looks the same is called the angle of rotational symmetry.

Characteristics of Rotational Symmetry

When a shape has rotational symmetry, it means that it can be rotated less than 360 degrees and still have the same appearance. The angle of rotation at which the shape looks the same is called the angle of rotational symmetry.

Finding the Angle of Rotational Symmetry

To find the angle of rotational symmetry of a shape, you can start by placing a protractor at the center of the shape and rotating it until the shape looks the same. The angle at which the shape looks the same is the angle of rotational symmetry.

Examples of Shapes with Rotational Symmetry

• A square has rotational symmetry of 90 degrees, as it looks the same after a 90-degree rotation.
• An equilateral triangle has rotational symmetry of 120 degrees, as it looks the same after a 120-degree rotation.
• A circle has rotational symmetry of 360 degrees, as it looks the same after any rotation.

Study Guide

Here are some key points to remember about rotational symmetry:

1. A shape has rotational symmetry if it looks the same after a certain angle of rotation.
2. The angle of rotational symmetry is the smallest angle at which the shape looks the same.
3. Some common shapes with rotational symmetry include squares, equilateral triangles, and circles.