PreAssessment: Which Shape is the Exception?  Section 1: Launch Similarity
Definition of Similarity and Similar Triangles
Lesson 1 of 11
Objective: SWBAT apply the definition of similarity to identify measurements in similar figures. SWBAT to argue that HL is a “similarity shortcut” for right triangles.
Launch Similarity
 Starting with the Facilitator, students will share out counterclockwise
 The Recorder/Reporter will document:
 The shape that is the exception in each set
 What they noticed about the corresponding sides and angles for each figure in the set
Resources (2)
Practice: Similar Polygons
A number of big ideas were introduced during the Launch section of this lesson. To give my students some time to think about what we've covered so far I will give them some familiar problems to work on. I plan to have students, in pairs, practice applying the definition of similarity to solve for missing angles and side lengths. After about 10 minutes of work time, I will pass out answer keys so that students can make corrections and ask clarifying questions.
Resources (3)
Resources (1)
Resources (1)
Resources
Something I Heard that Reinforced My Current Understanding of Similarity 
Something I Heard that Challenged My Understanding of Similarity 


Resources (1)
Resources (1)
Resources
Check for Understanding
Because we've done a lot of partner work during this initial similarity lesson, I want to provide my students with an opportunity to share their own thinking. On the back of the Graphic Organizer students used during the wholeclass discussion, I have provided a quick assessment. The assessment checks students' understanding (see page 2) by asking them to determine whether the triangles are similar. I make clear to students that I want them to take their time and use precise academic and geometric vocabulary to explain what they know and how they know it (MP6). In order to get a sense of the connectedness or depth of a student's understanding, I ask the students to show how they know in more than one way. Asking students to provide multiple explanations will give me greater insight into their thinking and understanding.
Resources (2)
I want students to apply what they learned in this lesson, which is why I give them this homework assignment. In Are the Triangles Similar?, students determine whether given pairs triangles are similar and justify how they know by showing work and writing similarity statements.
Resources (1)
Resources (1)
Resources
Similar Lessons
Radian measure Day 2 of 2
Environment: Suburban
Satellite Overflight 1
Environment: Rural
Dilation Nation
Environment: Suburban
 UNIT 1: Creating Classroom Culture to Develop the Math Practices
 UNIT 2: Introducing Geometry
 UNIT 3: Transformations
 UNIT 4: Discovering and Proving Angle Relationships
 UNIT 5: Constructions
 UNIT 6: Midterm Exam Review
 UNIT 7: Discovering and Proving Triangle Properties
 UNIT 8: Discovering and Proving Polygon Properties
 UNIT 9: Discovering and Proving Circles Properties
 UNIT 10: Geometric Measurement and Dimension
 UNIT 11: The Pythagorean Theorem
 UNIT 12: Triangle Similarity and Trigonometric Ratios
 UNIT 13: Final Exam Review
 LESSON 1: Definition of Similarity and Similar Triangles
 LESSON 2: Similarity Problem Solving and Proofs
 LESSON 3: Similarity Group Assessment
 LESSON 4: Introduction to the Slope Ratio (Tangent)
 LESSON 5: Solve Real World Problems with Clinometers
 LESSON 6: Introduction to Sine and Cosine
 LESSON 7: Problem Solving with Right Triangles and Trig
 LESSON 8: Context Problem Practice
 LESSON 9: The Soda Can Task: Trigonometry and Area Application
 LESSON 10: Review for Trigonometry Unit Assessment
 LESSON 11: Trigonometry Unit Assessment