Caliber Geometry Compass (Red)

Circles can be made by fastening one leg of the compasses into the paper with the spike, putting the pencil on the paper, and moving the pencil around while keeping the hinge on the same angle. The radius of the circle can be adjusted by changing the angle of the hinge. Distances can be measured on a map using compasses with two spikes, also called a dividing compass. The hinge is set in such a way that the distance between the spikes on the map represents a certain distance in reality, and by measuring how many times the compasses fit between two points on the map the distance between those points can be calculated. To use a compass, place the points on a ruler and open it to the measurement of ½ of the measurement of the circle that you want to draw. For instance, if you desire to draw a 3'' circle, open the compass to 1 ½ ''. Next, place the point (needle) on the spot that you wish the center of your circle to be, and then rotate the section that has the pencil lead around the point, using the handle.