Reflection: Student Ownership SAS-sy Triangles - Section 5: Practice/Homework and Exit Ticket


While checking the practice/homework assignment, I was excited to notice that many of my students were using shading techniques and making up their triangles.  In sample of student work for - marking Triangles 1, shows how a student might use a capital "S" to indicate that the side shared in common with both triangles.  By placing this "S" in the diagram, I find that students are more easily able to identify the reflexive property and also don't forget this as a congruent side.  This student example shows a student who just marked their diagram with congruent sides, angles and the reflexive S. 

Also, in this example of Student Work - Marking Triangles 2, you can see that both students named the angle that is bisected as <1 and <2 in the diagram.  This short-cut, I find, helps to keep my students more organized than naming all of the angles using three letters.  This is also a great trick for quickly noting that vertical angles and base angles in isosceles triangles are congruent as well.

  Student Ownership: More of Marking up Triangles
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SAS-sy Triangles

Unit 4: Tremendous Triangles
Lesson 4 of 10

Objective: Students will be able to identify when and how to prove triangles congruent using SAS congruence theorem.

Big Idea: In this student-centered lesson, students will explore and explain why the SAS congruence theorem works to prove triangles congruent.

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mark picture image sassy triangles
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