How To Use a Protractor

The circular or semicircular tool for measuring known as the protractor helps in measuring an angle or constructing an angle of a specified measure. Usually degrees are the units of measurement used here.

Tips to measure an Angle

1. First of all, locate the center point on the straight edge of the protractor.

2. After placing the hole over the vertex, or point, of the angle to be measured, assemble the zero on the straight edge of the protractor using one of the sides of the angle.

3. Now, you need to identify the point where the second side of the angle meets the curved edge of the protractor.

4. Then, you can easily read the number written on the protractor at the point of meeting. You can thus get the measure of the angle in degrees.

Tips to Construct an Angle

1. Using the straight edge of the protractor, first draw a straight line. You can see the line formed on one side of your angle.

2. Locate the center hole on the straight edge of the protractor.

3. After placing the hole over one end point of the line that have been drawn, line up the zero on the straight edge of the protractor using the line.

4. Create a mark at the number on the curved edge of the protractor that matches to the preferred measure of your angle.

5. By utilizing the straight edge of the protractor, connect the mark to the end point of the first line, thereby forming an angle.

Tips to measuring the reflex angle

For measuring the reflex angle, usually you have to start by measuring the angle and then subtracting it from 360. But using a protractor, you can easily do this by few steps. After turning the protractor over, start by measuring the angle. The pointer on the back will give you the number of degrees of the reflex angle.

Other Valuable Tips

A circle has 360 degrees where the straight line measures 180 degrees with the corner of a square measuring 90 degrees (right angle). Angles measuring below 90 degrees are acute angles and measuring more than 90 degrees are obtuse angles.