Reflections and rotations

What this chapter teaches

A reflection sends each point to the point the same distance on the other side of a mirror line. A reflection in y = x swaps the two numbers. A rotation needs a centre, an angle and a direction. A half turn needs no direction.

Three questions to ask

There is no one right wording. Listen for the idea.

1. Where does the point (2, 5) go in a reflection in y = x, and how do you know?
2. What three things do you need to describe a rotation?
3. Why does a reflection flip a shape over when a rotation does not?

After the chapter, the learner can

• Reflect a shape in a line like y = x
• Rotate a shape by 90° or 180° about a point
• Describe a rotation by its centre, angle and direction