While only one patent model for a protractor survives in the Smithsonian collections—from an inventor with a colorful personal history—several of the other objects also provide examples of technical ...

Protractors usually stop at 180°, which means reflex angles cannot be drawn by just following this method. To draw a reflex angle, for example PQR = 300°, calculate what the acute angle PQR ...

Position the protractor on top of the circle so that ... An appropriate title for this example would be ‘A pie chart to show mode of transport to school’. It is possible to interpret a pie ...