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
p. 2117Congruence 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.
45 degrees11
Exercise #3Can you prove that the two triangles are congruent?
Explain why or why not.
45 degrees12Exercise #4Can you prove that the two triangles are
congruent? Explain why or why not.
45 degrees13
Exercise #5Can you prove that the two triangles are congruent?
Explain why or why not.
45 degrees14Exercise #6Can you prove that the two triangles are
congruent? Explain why or why not.
45 degrees15Congruence Postulates
p. 21116Congruence 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 degrees19Exercise #2Can you prove that the two triangles are
congruent? Explain why or why not.
45 degrees20Exercise #3Can you prove that the two triangles are
congruent? Explain why or why not.
45 degrees21Exercise #4Can you prove that the two triangles are
congruent? Explain why or why not.
45 degrees22Exercise #5Can you prove that the two triangles are
congruent? Explain why or why not.
45 degrees23Exercise #6Can 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.
45 degrees28Exercise #3State if the two triangles are congruent?
If they are, justify your answer with a congruence postulate or
theorem.
45 degrees29
Exercise #4State if the two triangles are congruent? If they
are, justify your answer with a congruence postulate or
theorem.
45 degrees30
Exercise #5State if the two triangles are congruent? If they
are, justify your answer with a congruence postulate or
theorem.
45 degrees31
Exercise #6State if the two triangles are congruent? If they
are, justify your answer with a congruence postulate or
theorem.
45 degrees32
Exercise #7State if the two triangles are congruent? If they
are, justify your answer with a congruence postulate or
theorem.
45 degrees33Exercise #8State if the two triangles are congruent?
If they are, justify your answer with a congruence postulate or
theorem.
45 degrees34Exercise #9State if the two triangles are congruent?
If they are, justify your answer with a congruence postulate or
theorem.
45 degrees35
Exercise #10State if the two triangles are congruent? If they
are, justify your answer with a congruence postulate or
theorem.
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 _______________ .
109 degrees37