山东省临沂市蒙阴县2016_2017学年度八年级数学下学期期中试题.doc

1、 30 60 B A P 2016-2017 ( 90 120 ) 21 22 23 24 25 26 ( 3 36 ) 1 2 3 4 5 6 7 8 9 10 11 12 13 14 x 2 x 2 x 2 x 2 x 2 x 2. A 2 3B 3 C 9 D 12 3. 4 A 5 3= 2 B 3 5 2 3 6 15 C 2 2 2 =16 D 3 =1 34. AB=8 BC A. 43 3B.4 C. 83 D. 43 5. P 60 P 30 A P 30 B B P ( ) A 60 B 45 C 20 3 D 30 3 6. ( ) A 5 O D C B A B C D

2、 7 ABCD AC BD O E BC ( ) A OE 2 1 DC B OA=OC C D 8 ABCD AC BD O AD=8,BD=12,AC=6, ( ) A.13 B.17 C.20 D.26 7 8 10 9 A m n B ( 2 l ) C m n D A 2 l ) B 2 l ) C 1 2 ) D 1 2 ) 10. ABCD AC BD Q AD=23 DE=2 OCED A 23 B 4 C 43 D 8 11. a b c S1+S2=S3 A 1 B 2 C 3 D 4 F E D C B A O 11 12. AB=10 AC=2 10 BC AD=6 B

3、C A 10 B 8 C 6 10 D 8 10 13 ABCD AC BD O E F AD CD EF EF 2 BD 2 ABCD A 2 2 B 2 C 6 2 D 8 2 14 OABC O 0 0 B 2 2 O 60 D A 1 1 B 1 1 C 2 0 D 0 2 13 14 3 15 15. 5 3 _ 16 1 2 18 2 17. 1 2 x x x _. 18. ABC ACB=90 BC EF BC D 18 AB E BE=BF, BECF . 1C1 1 1 1 1C1 1 1B1C2 2 1B1C2 2 2B2C2 2 2 3 2016 _ 19 63 20.

4、 2 0 3 1 81 3 0 1 (3 ) 4 8 1 3 2 21. 10 1 1 a 1 12 21 2 2 a 1 23 32 3 3 a 1 32 23 4 4 a 1 25 52 1 n n a _ 2 1 2 3 n a a a a 22. 10 AB=15 BC=14 AC=13 22 AD x AD BC D BD = x x CD AD D C B A 23. 10 BD ABCD . 1 BD AD BC E F . 2 BE DF BEDF . 23 24. 11 1 M N AB AM MN BN AM MN BN M N AB . 1 M N AB BNMNAM.

5、AM=2 MN=3 BN 2 2 F M N G AB AD AE AC D E BC ECDEBD M N FG . 24 2016 2017 3 DBBDD DDBAA DCAB 3 15.6 16 22 2 18.AC=BC 19. 6048 2 AO= 2 3 BO=2 2 2 BO AO = 2 2 2 ) 2 3 ( = 2 5 AB1 B1C2= 2 3 2 5 2=6 B2 6 B4 B2016 2 2016 B2016 6048 2 20. 2 0 3 1 81 3 2 1 2 2 2 2 3 3 21. 11 1 4 2 6 1 1 nn 2 1 2 3 n a a a a

6、 21 32 1 nn 11 n 22. 10 D BD = x 14 CD x E F D C B A 2 2 2 2 2 15 AD AB BD x 2 2 2 2 2 13 (14 ) AD AC CD x 22 15 x 22 13 (14 ) x 9 x 12 AD 1 2 ABC S BC AD 1 14 12 84 2 23. 11 1 4 2 6 1 . 2 BEDF BD DE BF DF EF DF BF BEDF 24. 11 M N AB BNMNAM, AM MN=3 2 2 2 BN MN AM 9 4 13 BN= 13 F M N G AB AD AE AC FM MN NG ABD ADE AEC BD=2FM DE=2MN EC=2NG D E BC ECDEBD 2 2 2 EC DE DB 2 2 2 4 4 4 NG MN FM 2 2 2 NG MN FM M N FG 25. 12 4 (1) EFGH AC AB BC EF= 1 2 AC H AC BD GH= 1 2 AC EF=GH EFGH (2) AC=BD EFGH (1) EFGH AC=BD FG= 1 2 BD EF= 1 2 AC EFGH EFGH (1) EFGH AB BC F CD BC EFGH