APR Deluxe Int'l Protractor & Parallel Rule Plotter [DCPP-5]

what tool is needed to measure angles we use rulers meter sticks to measure length beakers and measuring cups for liquid volume and even scales to measure weight but what tool is used to measure angles in this lesson you will learn what tools use to measure angles by exploring the properties of protractors let's review a circle is a curved figure and any point along the edge is the same distance from the center an angle is formed when one ray rotates around a common endpoint shared with another ray measurement tools have standard markings that are consistent one centimeter is the same length on any centimeter ruler a one degree angle is always one three hundred sixtieth of a circle when measuring length a straight edge is needed but angles aren't straight they represent how much one ray has rotated so a standard ruler won't work a new tool is needed believed to be related to ancient cal