1.2

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1.2 Use Segments and Congruence

• Geometry
• Ms. Rinaldi

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Postulate

• In Geometry, a rule that is accepted without
  proof is called a postulate or axiom.

Postulate 1 The Ruler Postulate
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EXAMPLE 1
Apply the Ruler Postulate
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Apply the Ruler Postulate
EXAMPLE 2
Use a ruler to measure the length of the segment
to the nearest inch.
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Definition

• Between

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Postulate 2 Segment Addition Postulate
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EXAMPLE 3
Apply the the Segment Addition Postulate
SOLUTION
Because Tulsa, Oklahoma, lies between Lubbock and
St. Louis, you can apply the Segment Addition
Postulate.
LS LT TS 380 360 740
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Find a length
EXAMPLE 4
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EXAMPLE 5
Find a length
SOLUTION
Use the Segment Addition Postulate to write an
equation. Then solve the equation to find GH.
Segment Addition Postulate.
Substitute 36 for FH and 21 for FG.
Subtract 21 from each side.
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Find a length
EXAMPLE 6
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Definition

• Congruent Segments

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EXAMPLE 7
Compare segments for congruence
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Compare segments for congruence
EXAMPLE 8
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Homework

• Pages 12 13 1, 6-14, 20, 21-23