(1)?????A ?B ?C ?D ?E?????

1
????
???????????,????????????
2
(1)?????A ?B ?C ?D ?E?????
3
(2)?????A ?B ?C ?D ?E ?F?????
4
??????
??????? ???
5
??
????
??????????????????,???????????????,????????(?????
???????)??????????
?????
A
3
4
6
1
B
C
2
5
6




???????????
(1) ??
??
?
?CBD(??)?ABC(????)180
7
???????????????????
????
(1)????????,???????????????????? (2)??????????,???
???????? (3)????????????????????,???????????,?????
????????????????
8
???????ACD ?B ? A
D
???????????????????????
9
D
?ACD ?ACB180
?
?A ?B ?ACB180
??, ?A ?B ?ACD
10
A
??C?CE???AB
?1 ?B
D
B
C
?2 ?A
?1 ?2 ?A ?B
??ACD ?A ?B
11
???????????????????????
?ACDgt ? A
?ACDgt ? B
???????????????????????
?????????????????????
12
gt
gt
13
?1
???????1???.
2
14
???????1???
15
???
1????????????????????( ) 2??????????????????(
) 3????????????????????????(
) 4??????????????????( ) 5?????????????????????
???( )
16
?
?
???ADC??ABD???,
?ADC?B?BAD80
??
? ?B?BAD
?
??ABC?,
???B?BAC?C180
???C 180- ?B-?BAC
70
180-40-70
17
???????????
1????????180
2????????????
(1)????????????????????????
(2)???????????????????????
(3)???????????????????????
18

• (C?) P82 T3?4
• (B?)?C??????P82 T5?6
• ??????????????????

????
19
??(A\B)(??)
1????????????????????????180,????????( ) 2?
?1, ?2, ?3??ABC???, ??1?2?3234,? ?ABC??(
) 3??????????????
20
????
A?
????D??ABC?AC????,?C?DBC, (2)??A ?BDA,
?ABD40 ??C???
40o
D
21
??C30,??A ?B ?D ?E??
22
???????????
?ACB
?BAC
?ABC
????????
?1?2?3?ACB?CAB?ABC540
23
???????360
24
?2 ?ABC180
?3 ?ACB180
????????
?1 ?2 ?3 ?BAC ?ABC?ACB540
??BAC ?ABC?ACB180
?1 ?2 ?3360
25
A
1
3
??A?AD???BC
B
?3 ?4
C
2
?2 ?BAD
?2 ? 3 ? 4?BAD
??, ?1 ?2 ?3 ?1 ?4 ?BAD360