The Circle Protractor
Teacher’s Corner: This is a high quality, beveled 6" (15.24cm) circle protractor. It is made by the Staedtler company and costs about $15.00. I had six of these  standard circle protractors in my classroom. The circle protractor was the most important instrument/tool in my classroom.
I also encouraged through a  note to my student’s parents that a personal protractor would be useful at home to complete their child's school work.
The Template
Above is a square, (16cm x 16cm), piece of white hardboard, also called Masonite. There were ten of these stacked on top of each other on my template wall in my class. It was a standard template in high use. The opposite side was a mini blackboard.
Tracing the Templates Perimeter
Place the template on the back of a cereal box and trace around the perimeter.