1. a What sizes of angle (from 0 to 360) can it be used to measure?
Angles
GM3.2 Extension Starter
Here is a circular protractor which has been cut into pieces like a puzzle.
a What sizes of angle (from 0 to 360) can it be used to measure?
b The circular protractor has five pieces.
Can you find a way to measure the same
angles, but using only four pieces?
Preamble
This is a short investigation based on a circular protractor. Pupils tend to forget about angles greater than 180, so they might need nudging in this direction.
Possible content Mental arithmetic, trial and improvement.
Resources
None.
Solution/Notes
These angles may be measured: 30°, 60°, 90°, 120°, 150°, 180°, 210°, 240°, 270°, 300° and 330° Two ways to measure the same angles by splitting the protractor into four pieces are shown below.