Lesson plan

Find an indirect measurement by using similarity criteria

teaches Common Core State Standards CCSS.Math.Content.HSG-SRT.B.5 http://corestandards.org/Math/Content/HSG/SRT/B/5
teaches Common Core State Standards CCSS.Math.Practice.MP1 http://corestandards.org/Math/Practice/MP1
teaches Common Core State Standards CCSS.Math.Practice.MP3 http://corestandards.org/Math/Practice/MP3
teaches Common Core State Standards CCSS.Math.Practice.MP8 http://corestandards.org/Math/Practice/MP8

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Big Ideas: We can use similar triangles to find an indirect measurement. The tasks in this lesson require students to use similar triangles to solve for a missing side when it cannot be directly measured. Students will use prior knowledge of similar triangles using the AA criteria and proportional sides to solve for the missing side. Students will also use the Pythagorean Theorem to solve for a missing side of a right triangle. This lesson leads into the trigonometric functions and students' understanding of why those functions exist. Vocabulary: similarity, dilate, scale factor, proportionality, SAS similarity