1. Symmetries of plane shapes
GM5.1 Core Plenary
Here is a pattern drawn on isometric paper.
Klara says that it has rotation symmetry order 4 and two lines of reflection symmetry. Is she right?
Copy the pattern and reflect it in the dotted line. What is the difference between the original pattern and the reflection?
Draw a few more similar patterns on isometric paper. Jot down the order of rotational symmetry and the number of lines of symmetry each one has.
Preamble
Pupils will have the chance to use their knowledge of symmetries of plane shapes in an open-ended context. The idea of sense in reflections in dealt with informally.
Possible content Reflection and rotational symmetry.
Resources
Isometric lined or dotty paper.
Solution/Notes
Klara is wrong – the pattern has rotation symmetry order 2 and no lines of reflection symmetry.
When the pattern is reflected in the dotty line,
the direction of the arrows is reversed.
Pupils’ own patterns with number of lines of reflection and order of rotational symmetry.