1. Reflection, rotation and translation
GM3.2 Core Starter
Here are eight
identical L-shapes.
A maps to D by a reflection in the blue line.
Describe fully the following mappings.
C → F
B → C
H → C
A → E
Is it possible to map each shape onto all the other shapes with a single transformation (a reflection in a coloured line, a translation or a rotation about R)?
Preamble
An activity to check on recall of previous work on transformations. Pupils may need reminding as to how to describe transformations fully. There are several ways of working the activity – in small groups with a short whole-group summing up or as a whole-group activity focussed on the whiteboard.
Possible content
Using and describing reflections, rotations and translations.
Resources
Possibly squared paper and tracing paper (for the rotations).
Solution/Notes
C → F reflection in the green line B → C reflection in the blue line H → C translation 4 squares right and 4 squares up A → E rotation 180 about R
The following are the only mappings that cannot be achieved by a single reflection, translation or rotation about R (some are possible using rotations about other points):
A  G, A  H, B  G, B  H, C  G, D  H, E  G, E  H, F  G, F  H.
Original Material © Cambridge University Press 2009
Original Material © Cambridge University Press 2009