EDEXCEL GCSE Foundation Maths - Rotations
What is a Rotation?
A rotation is a transformation that turns a shape around a fixed point called the centre of rotation. The shape is turned by a certain angle of rotation.
Key Terms:
- Centre of rotation: The point around which the shape is rotated.
- Angle of rotation: The amount of turn, measured in degrees.
- Direction of rotation: Clockwise or anticlockwise.
How to Rotate a Shape:
- Identify the centre of rotation. This is usually marked with a dot.
- Determine the angle of rotation. This is usually given in degrees.
- Decide the direction of rotation. This is usually specified as clockwise or anticlockwise.
- Rotate each point of the shape around the centre of rotation by the given angle.
- Connect the rotated points to form the image of the shape.
Example:
Let's say we want to rotate a triangle ABC 90 degrees clockwise about point O.
- Centre of rotation: O.
- Angle of rotation: 90 degrees.
-
Direction of rotation: Clockwise.
-
Step 1: Place your pencil on point A and turn it 90 degrees clockwise around point O. Mark the new position as A'.
- Step 2: Repeat this process for points B and C, marking the new positions as B' and C'.
- Step 3: Connect A', B', and C' to form the rotated triangle A'B'C'.
Things to Remember:
- The size and shape of the shape remain the same after a rotation.
- The orientation of the shape changes.
- The distance between each point and the centre of rotation remains the same.
Practice:
- Try rotating various shapes around different centres of rotation and angles.
- Use a ruler and protractor to help you accurately rotate the shapes.
- Practice identifying the centre of rotation, angle of rotation, and direction of rotation from diagrams.
Note:
- You can also use tracing paper to help you visualize the rotation.
- There are many online tools and apps that can help you practice rotations.