How To Use A Protractor
A protractor is a tool that allows you to measure an angle or construct an angle of a given measure.
To Measure an Angle
Step 1
Find the center hole on the straight edge of the protractor.
Step 2
Place the hole over the vertex, or point, of the angle you wish to measure.
Step 3
Line up the zero on the straight edge of the protractor with one of the sides of the angle.
Step 4
Find the point where the second side of the angle intersects the curved edge of the protractor.
Step 5
Read the number that is written on the protractor at the point of intersection. This is the measure of the angle in degrees.
To Construct an Angle
Step 1
Use the straight edge of the protractor to draw a straight line. This line will form one side of your angle.
Step 2
Find the center hole on the straight edge of the protractor.
Step 3
Place the hole over one end point of the line you have drawn.
Step 4
Line up the zero on the straight edge of the protractor with the line.
Step 5
Make a mark at the number on the curved edge of the protractor that corresponds to the desired measure of your angle. For example, mark at 90 for a 90-degree angle.
Step 6
Use the straight edge of the protractor to connect the mark to the end point of the first line, forming an angle.
Things Needed
- Protractors
- Notebook Papers
- Pencils And Erasers
TL;DR (Too Long; Didn't Read)
There are 360 degrees in a circle. A straight line measures 180 degrees. The corner of a square measures 90 degrees. This is called a right angle. Angles that measure fewer than 90 degrees are called acute angles. Those measuring more than 90 degrees are called obtuse angles.
Cite This Article
MLA
Contributor, . "How To Use A Protractor" sciencing.com, https://www.sciencing.com/protractor-12928/. 24 April 2017.
APA
Contributor, . (2017, April 24). How To Use A Protractor. sciencing.com. Retrieved from https://www.sciencing.com/protractor-12928/
Chicago
Contributor, . How To Use A Protractor last modified March 24, 2022. https://www.sciencing.com/protractor-12928/