Protractors usually have two sets of numbers going in opposite directions. The outer set usually measures angles opening to the left, and the inner set measures angles opening to the right. Be careful which one you use! When in doubt think "should this angle be bigger or smaller than 90° ?" Have a Go Yourself!

Protractor, in math, is considered to be an important measuring instrument that is in the shape of a semi-circle. The common protractor is a translucent tool that helps us measure angles in degrees. A radian scale protractor measures an angle in radians.

Most protractors measure the angle in degrees but there are few protractors available that can measure angles in radian, they are known as Radian-scale protractors. Let us see step by step how to measure an angle using a protractor, Step 1: Suppose an angle given ∠AOB, whose measure we need to find out.

This is a transparent online protractor, you can easily measure the angle of any object around you, and it helps you measure angles in a picture, taking a picture and uploading it, then dragging the midpoint of the protractor to the vertex of the angle, our virtual protractor is very accurate, it can zoom in, zoom out, rotate and move position.

A protractor is a semicircular geometry tool divided into 180 equal parts, each measuring 1°. It is used for drawing angles of known measures and finding angles of unknown measures and is usually made of transparent plastic, glass, steel, or wood. The geometry protractor have two scales marked on it: outer and inner.

2021年2月23日 · Welcome to this free lesson guide where you will learn how to read a protractor and how to use it to measure angles. This complete guide on how to use a protractor includes several examples, an animated video mini-lesson, and a …

For extra tips and practice problems, check out IXL's measuring angles with a protractor lesson! Remember how one side of the angle traces out a circular arc? We use that circle to measure how big the angle is. We look at how much the angle has “opened” as compared to the full circle. Angles are measured in degrees.