A full circle protractor can be used to measure angles too large for a standard semicircular protractor. Making your own from a paper plate is a craft project that can also help learners to better understand the relationship between angles and circles in general.
Choose a paper plate with decorative fluting or scallops around the edge. Many brands have exactly 36 or 72 sections. If this is the case, choose a starting place then pencil in degrees in increments of 5 or 10 until you reach full circle. If not, divide 360 by the number of sections and mark the plate accordingly.
Draw a straight line across the centre of the plate, connecting the "0" degrees mark with the "180" degrees mark. Line up the ruler with the "90" degree and "270" degree marks. Mark a vertical line one inch long starting at the centre line. The point where these two lines meet is the centre of your protractor.
- A full circle protractor can be used to measure angles too large for a standard semicircular protractor.
- Draw a straight line across the centre of the plate, connecting the "0" degrees mark with the "180" degrees mark.
Use the scissors to cut out a half-moon shape above the centre line. Ensure the numbers denoting the degrees are left in place. This will produce a viewing window making it easier to measure angles. Your protractor is now ready for use.
If your paper plate has no edging, enlarge and print out the image of a protractor in the Resources section and glue this to the plate.