2024年北师大版九年级上册数学同步学与练第四章图形的相似专题13探索三角形相似的条件（5个知识点4种题型1种中考考法）（解析版）.pdfVIP

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倍速学习四种方法

1.

2.1

3.2

4.3

5.

1.

2.

3.

4.

.

1.

2.

3.

4.

1.

ABDEABBCAC

ABCDEFQÐA=ÐDÐB=ÐEÐC=ÐF\=,==.

BCEFDEEFDF

\ABCDEF.

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1().

A.B.

C.D.

C

A

BD

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C.

2.1

ABCABCÐA=ÐAÐB=ÐBABCABC

11111111

2VABCVADEÐC=ÐEÐ1=Ð2△ABC∽△ADE

Ð1+ÐDAC=Ð2+ÐDACÐBAC=ÐDAE

∵Ð1=Ð2

∴Ð1+ÐDAC=Ð2+ÐDAC

∴ÐBAC=ÐDAE

∵ÐC=ÐE

∴△ABC∽△ADE

3.2

ABAC

ABCABCÐA=ÐA=ABCABC

1111111

ABAC

1111

A

A1

BCB1C1

DEVABCABACAD=3，AB=8，AE=4，AC=6

3

△ADE△ACB

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∵AD=3，AB=8，AE=4，AC=6

ADAE1

\==

ACAB2

∵ÐDAE=ÐCAB

∴△ADE△ACB

4.3

ABBCCA

ABCABC==ABC∽ABC

111111