It will quickly become a valuable tool in your math skills. A protractor is easy to use once you understand its parts and their purpose. Most of them are semi-circular, but there are 360-degree versions available. What can you measure with a protractor?Ī protractor can be either a round or a semi-circular tool. In addition, students would often guess at the number, resulting in incorrect calculations.īut, other students may thrive during this lesson because of the tactile tasks and visualization.
One of the main challenges students face is determining which measurement on a protractor to look at, especially if they don’t know which row of numbers to look at.įor instance, a 60-degree angle would be on the left, but the next row would be on the right. Needing to use reading and memorization skills to learn and access math skills is one of these times. Keep that in mind if you have a struggling student. If you have unidentified learning disabled students in your class, this is one of those times when their skill deficiencies will compound. It also teaches students vocabulary related to angles and its properties. Times like this is when I introduce the ‘power of yet.’ If a student exclaims “I can’t do this!” or “I don’t understand this!” I remind them to take a deep breath and say “yet.”Ī protractor is not just a tool to calculate angles.
Especially if this is a new tool and concept for them. Initially, your students may struggle with using a protractor. You will be able to find the angle’s value. Then, line up the other side of the angle with the 90-degree scale on the inner side of the protractor. You should align the 90-degree scale on one side of the protractor with the 0 degree line on a map, which is located on the right side. Once you have reached the desired angle, the number of one-degree curves on the curved edge of the protractor’s outer scale will equal the degree of the angle.Ī protractor has two scales, one for degrees and one for millimeters. To use a protractor, line the angle with one end of the protractor’s curved edge, then place the ruler on the other side of the curved edge, and count the number of degrees along each curve until the other ray is located. In most cases, they have a circle or cross in the middle. How is a protractor used?Ī protractor is a tool for measuring angles. And for some students, the visualization and hands-on activities adds in some multi-sensory learning that helps them learn better.
#Geometry protractor software#
The need for using protractors is becoming less popular as a result of computer software and the internet. Both types of protractors have a graduated circle and a pivoting arm. There are two basic types: the circular and the semicircular.
You can also read a protractor by using its baseline, which is the side that has zero.Ī protractor is a simple tool used for calculating angles. The device has a number scale that goes from zero to 180 degrees, with one side of the angle lining up with 0 on its inner scale and a cosine scale on its outer scale.īy lining up these scales, you can measure angles accurately and get the right answer. What is a protractor?Ī protractor is a tool used in mathematics to calculate angles. Here are some of the most common uses of a protractor. In this example, ∠ABD=120 and ∠CBD=60.And what can you measure with a protractor? This article will explain the basics.
Note that the middle letter denotes the vertex point of the angle.įor example, notice how in the diagram below that both angles ∠ABD and ∠CBD have point B as their vertex, but have different measures?
#Geometry protractor how to#
This complete guide on how to use a protractor includes several examples, an animated video mini-lesson, and a free worksheet and answer key.īefore we learn how to use the protractor tool to measure angles, let’s do a super quick review of angle notation (understanding this important skill will make learning how to use a protractor much easier).Īngle Notation: In geometry, an angle is denoted by the ∠ symbol and includes 3 consecutive letters which represent the three points that form the angle. Welcome to this free lesson guide where you will learn how to read a protractor and how to use it to measure angles.
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