Learning Goal: IWBAT to determine whether two triangles are congruent by using the triangle congruence postulates and theorem. Homework : HW 3.5: Triangle

August 7, 2012

Learning Goal:IWBAT to determine whether two triangles are congruent by using the triangle congruence postulates and theorem. Homework: HW 3.5: Triangle Congruence Worksheet-------------------------------------------------------------------Do Now:

September 13, 20131) Sit. 2) Materials out. 3) Backpacks away. 4) Do Now SILENTLY.

Complete each congruence statement by naming the corresponding angle or side.

Students take out Do Now sheets.Remind students to take out homework to be checked, copy new homework assignment in their agenda, and copy down learning goal BEFORE beginning the Do Now problem.Take roll first, then go around and check homework as students are working.

1Agenda:Do Now (15 min)Exploring Triangle Congruence (20 min)SSS and SAS Congruence (15 min)Triangle Congruence Whiteboard (10 min)ASA and AAS Congruence (10 min)Triangle Congruence Whiteboard (10 min)Closure (5 min)Triangle Theorems Quiz (30 min)

2Exploring SSS Congruence

p. 211 in textbook. Inform students that we will use straws instead of pencils. They will mark the vertices formed by the straws by drawing a point with their pencil. 3Exploring SAS Congruence

p. 2114Draw ConclusionsWhat did you notice about the triangles you made with the three straws? What did you notice about the triangles you made with two straws and a 45 angle between them?If you know that two sides of a triangle are congruent to two sides of another triangle, what other information do you need to tell whether the triangles are congruent?

Explain the activity to the class. Activity is open notes/ open book. 5Congruence Postulates

p. 2116Congruence Postulates


Decide whether enough information is given to prove that the triangles are congruent. If there is enough information, tell which congruence postulate you would use.p. 2118Triangle Congruence ActivityTeacher will project two triangles at a time on the board. Your task is to determine whether it is possible to prove that the two triangles are congruent. If so, then state the congruence theorem you would use to prove it.1 min. independently journal, then 2 min. partner pair share per exercise.Teacher will call on students to share and justify their responses.Explain the activity to the class. Activity is open notes/ open book. 9Exercise #1Can you prove that the two triangles are congruent? Explain why or why not.

45 degrees10Exercise #2Can you prove that the two triangles are congruent? Explain why or why not.

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Exercise #3Can you prove that the two triangles are congruent? Explain why or why not.


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Exercise #5Can you prove that the two triangles are congruent? Explain why or why not.


45 degrees15Congruence Postulates


p. 21117Triangle Congruence ActivityTeacher will project two triangles at a time on the board. Your task is to determine whether it is possible to prove that the two triangles are congruent. If so, then state the congruence theorem you would use to prove it.1 min. independently journal, then 2 min. partner pair share per exercise.Teacher will call on students to share and justify their responses.Explain the activity to the class. Activity is open notes/ open book. 18Exercise #1Can you prove that the two triangles are congruent? Explain why or why not.






45 degrees24Other Congruence Postulates?Angle-Angle-Angle (AAA) Congruence Postulate?http://www.mathopenref.com/congruentaaa.html

Side-Side-Angle (SSA) Congruence Postulate?http://www.mathopenref.com/congruentssa.htmlIf triangles satisfy AAA or SSA, then the triangles are not necessarily congruent.25Triangle Congruence Whiteboard Activity Students work in pairs. Each pair receives a whiteboard, marker, and eraser. Teacher will present practice exercises about the congruence of triangles on the board. Your teams have 1 minute to solve the problem and write the answer on the whiteboard with its justification.Display your whiteboard when the timer runs out.Explain the activity to the class. Activity is open notes/ open book. 26Exercise #1State if the two triangles are congruent? If they are, justify your answer with a congruence postulate or theorem.

45 degrees27Exercise #2State if the two triangles are congruent? If they are, justify your answer with a congruence postulate or theorem.


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Exercise #4State if the two triangles are congruent? If they are, justify your answer with a congruence postulate or theorem.

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45 degrees36ClosureTake a moment to response to the following prompt in your notes. Please include a drawing along with an explanation.If three angles of a triangle are the same as three angles of another triangle, are both triangles congruent?The triangles are congruent because ____________________ . The triangles are NOT congruent because _______________ .

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Learning Goal: IWBAT to determine whether two triangles are congruent by using the triangle congruence postulates and theorem. Homework : HW 3.5: Triangle