Transcript GEOMETRY Section 7.3: Triangle Similarity: AA, SSS, & SAS

BASIC GEOMETRY
Section 7.3: Triangle Similarity: AA, SSS, & SAS
Proving Triangles are Similar
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AA ~ Thm: If two angles of one triangle are congruent to
two angles in another triangle, then the triangles are
similar.
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SSS ~ Thm: If the 3 sides of one triangle are proportional
to 3 sides of another triangle, then the triangles are ~.
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SAS ~ Thm: If two sides of one triangle are proportional
to two sides of another and the included angles are
congruent, then the triangles are ~.
Proofs
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These 3 Thms are used the same as the congruent
triangles ones in proofs.
Properties of Similarity
Example 1: Explain why the triangles are
similar and write a similarity statement.
Example 2: Verify that the triangles are
similar.
A) ∆PQR & ∆STU
B) ∆DEF & ∆HJK
Example 3: Explain why ∆ABE ∼ ∆ACD,
and then find CD.
Example 4: The photo shows a gable roof.
AC // FG. Find BA to the nearest tenth.
Assignment #3
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Page 474 #’s 1-6,9,10,34-36,(44)