Measuring Angles

Teaching students how to use a protractor to measure and identify angles can be one of the most enjoyable parts of a geometry unit. The protractor is a unique manipulative tool that students feel good about mastering. If you don't have a set of protractors in your room, send an email to your colleagues asking if anyone has some you can borrow. I'm sure someone will be able to supply you with a set.  

Before teaching how to identify angles, how to use a protractor, and how to determine a measurement value for angles, I have found it wise to have a discussion about angles - which is the main idea behind this article.

Ask students, "What is an angle?"  This basic question usually leads to some lively discussion, and you will get many interesting answers. The answer is sometimes difficult to put into words - but it makes for a great starting point.  The answer is, "An angle is formed at the point where two lines come together." On the board, draw a right angle (which makes a 90 degree square corner), an acute angle (less than 90 degrees), and an obtuse angle (greater than 90 degrees).  Ask students what differences they see between the angles.  "One is bigger....one is smaller.... one is straight," are the types of responses you may get.  Then, have students stand up and make different types of angles using their arms.

Next, lead a discussion in which students are asked to identify how people use angles in everyday life. For example, carpenters use angles to construct buildings, skateboarders use angles to make their ramps, cars have to be parked at certain angles to fit into their spaces, and a person playing pool has to figure out the correct angle in order to get the ball in a pocket.

At this point, introducing the vocabulary associated with angles is appropriate. In order to help students remember vocabulary that is associated with each angle, I like to use a play on words.  For example, an angle that has a square corner is "just right," so it is a right angle.  An angle that is smaller than a right angle is "so cute," so it is an acute angle. An angle that is larger than a right angle is "obviously big," so it is an obtuse angle. Finally, the point where the two lines meet is called the vertex - I haven't yet thought of a good hint for that one!

Now that the students have had a chance to think about angles, I would recommend getting into one of the lessons I have highlighted below.  An excellent place to start would be the lesson entitled, "Measuring Angles".  It is geared toward fourth through fifth grades, but can be used with other grade levels as well. A terrific lesson to start out with for the younger students is, "An Introduction to Angles".

Measuring Angles Lesson Plans:

Measuring Angles

Students explore angles found in their classroom. They utilize worksheets imbedded in the lesson plan to gain experience measuring, and identifying different types of angles. This well-thought-out lesson is an ideal place to begin your exploration of angles.

An Introduction to Angles

Students utilize popsicle sticks to create a variety of angles, then use a protractor to measure the angles they create.  I love the simple, yet effective, use of popsicle sticks as a manipulative tool! This fun lesson will be especially beneficial for your kinesthetic learners.

Do You Measure Up?

Students participate in a variety of technology-based activities which will strengthen their understanding of measuring angles. This incredible lesson is geared toward upper elementary/middle school students, and should be highly motivating for our many students who love utilizing computers while they are learning.

Angles in Art

Students look at images by famous artists, and discover that artists use angles to create their pieces. Then, students create their own artwork by using angles and color.  This innovative lesson combines art and math in a wonderful way, and is especially good for visual learners.

Discussion Question:

How do you introduce the concept of angles to your students?