Congruent and Similar Triangles

 

This is one lesson in a larger Unit Plan that introduces triangular relationships through the lens of building a treehouse with a variety of triangular characteristics.  It has proofs, real world problems, constructions, a unit project, assessments, and more. In Lesson 19, “I'm Bored",  students use the conditions that make triangles congruent including SSS, AAA, SAS, ASA, AAS, and SSA, along with the conditions for Similarity SSS, and SAS, to complete the scale drawing and model of their treehouse. In addition they must use area formulas to determine the amount of materials needed to construct the the real world treehouse.    The entire unit plan can be found here. This lesson is part of the Unit Project. The project is group work, so it is easy to include differentiation. This is the truly hands-on part of the project as students finish their scale drawings and calculate materials. The rest of the project is found in lessons 3, 5, 8, 11, 15, & 20.

Weblink address (URL): 
Congruent and Similar Triangles

Standards & Objectives

Essential and guiding questions: 

From Lesson 16:

  • What are the differences and similarities between congruence and similarity?
  • When is being similar “good enough”?

From Lesson 17:

  • How are the theorems in this lesson connected?
  • Which of these theorems would appear to most useful in the real world?

From Lesson 18:

  • How are congruent triangles and similar triangles the same and different?
  • How are congruence relationships useful in everyday life?

Lesson Variations

Blooms taxonomy level: 
Understanding

Helpful Hints

Materials: 

  • pencil
  • paper
  • calculators for their scaled drawing
  • and any available resources that might be helpful in their construction of the scale model.

References

Contributors: 
Lisa Leach
Originator: 
Ayers Institute for Learning & Innovation