1

Warm-Up--Nov. 18, 19, 2009

2x + 3

5

3x - 1

1. 2.

2x - 3

3x - 9 x + 3

x y

62

3.

30x45 y

62

4.

2

Math Tech III

4.3-Congruent Triangles

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Corresponding sides: Corresponding angles:

K

M

L P

R

Q

• Triangles are congruent if all pairs of corresponding angles are congruent and all pairs of corresponding sides are congruent.

Corresponding Parts

Congruency Statement:      <K ≅ <P

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If    ABC        RST, name the corresponding parts.≅EX. 1

HINT: (The order of the letters in the names show which parts correspond.)

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Ex. 2

1.  What < in    ABC is ≅ to <F in    DEF?

2.  Which side of   DEF is ≅ to AC in     ABC?

ABC ≅      DEF

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congruency postulates

Side­side­side

Side­angle­side

Angle­side­angle

  Angle­angle­side

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Ex. 1 Are these triangles congruent?

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Ex. 2D is the midpoint of both GE and FH.Can you prove that the triangles are congruent?

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Ex. 3EF ≅ GH and EF || GH.Can you prove these triangles are congruent?

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Ex. 4 D is the midpoint of AC and AB ≅ CB.Can you prove any triangle congruent?

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Ex. 5CD = XYDE = YZm<C = m<X

C

D

EX

Y

Z

Can you prove that these triangles are congruent?

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Warm-Up--Nov. 20, 23, 2009

2. Name the four postulates for determining if two triangles are congruent.

1.

14

Are these triangles congruent?

Ex 7.

Ex 8.

Ex 9.

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http://regentsprep.org/Regents/mathb/1b/Reccontri.htm

http://www.quia.com/jq/13641.html

http://education.yahoo.com/homework_help/math_help/problem_list?id=minigeogt_4_1

http://www.glencoe.com/sec/math/studytools/cgi­bin/msgQuiz.php4?isbn=0­07­829637­4&chapter=4&lesson=4&quizType=1&headerFile=4&state=na

http://www.glencoe.com/sec/math/studytools/cgi­bin/msgQuiz.php4?isbn=0­07­829637­4&chapter=4&lesson=5&quizType=1&headerFile=4&state=na

http://www.glencoe.com/sec/math/studytools/cgi­bin/msgQuiz.php4?isbn=0­07­829637­4&chapter=4&lesson=2&quizType=1&headerFile=4&state=na

http://www.glencoe.com/sec/math/studytools/cgi­bin/msgQuiz.php4?isbn=0­07­829637­4&chapter=4&lesson=1&quizType=1&headerFile=4&state=na