Introducing Angles

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SWBAT define angles and identify their parts; SWBAT create and interpret notation and diagrams involving angles; SWBAT identify real-world examples of angles and angular measures

Big Idea

Angles are all around us...just swivel your head and have a look. In this lesson, students are introduced to angles and angular measures. They also learn to create and interpret geometric notation and diagrams involving angles.

Concept Development

30 minutes

In this section, we develop some pretty basic, but important, knowledge related to angles. The medium for this section is the Introducing Angles PowerPoint slideshow. The style of the PowerPoint is to not explicitly call out the concepts and relationships, but rather to provide examples that students can use to make inferences. So I don't say much as I'm going through the slides. Instead, I show the cases, and then focus my energy on stirring up a good classroom dialogue.  I focus on developing students' ability to speak articulately using complete sentences, conveying complete thoughts, and using academic vocabulary where appropriate.


So for example, when asked to share their conjecture about the meaning of the arc symbols on the angles in the slides, a student might say, "it shows that they're congruent". I would help this student to revise their statement to something more like "I infer that placing matching arc symbols on two angles indicates that those angles are congruent."


Throughout the PowerPoint presentation, I also pause frequently to check for understanding using student whiteboards. For example, after the slide on complementary angles. I might ask the students to draw a diagram that shows complementary angles. Or I might give them an angle measure, and ask them to indicate the measure of its complement.

Investigating Real Angles

30 minutes

For this section, we head to the computer lab to complete the Real Angles activity. In part 1, I have students investigate one of the most widely used forms of angular measurement: Latitude and Longitude.

Next, students create a PowerPoint slideshow that illustrates the terminology from this lesson using real-world images.