2023北京海淀区初二期末(下)数学试卷及答案.docx

海淀区八年级数学参考答案 2023.07 一、选择题（共 24 分，每题 3 分） 题号 1 2 3 4 5 6 7 8 答案 C B D A C A D D 二、填空题（共 18 分，每题 3 分） 9．110 10．③ 11．4 12．86 213． 4 2 14．左 4 （第一空 2 分，第二空 1 分） 三、解答题（共 58 分，第 15 题 6 分，每题 3 分，16~21 题，每题 4 分，21~24 题，每题 5 分，24 题 5 分，25 题 6 分，26 题 7 分） 55515．（1）解：原式= 2 ? 2 ? 3 5 5 5  ································ ································ 2 分 = 3 5 ． ································ ································ ··············· 3 分 16（2）解：原式= 16 = 4 ? 2 ? ································ ································ ·········· 4 分 4································ ································ ················ 5 分 4 = 2 ． ································ ································ ·················· 6 分 16．证明：如图，连接 AC，交 EF 于点 O. ∵四边形 ABCD 是平行四边形， ∴ BO ? DO ， AO ? CO . ······················ 1 分 ∵ BE ? DF ， ∴ OB ? BE ? OD ? DF . 即 FO ? EO . 3 分 A ∴四边形 AECF 是平行四边形. ············· 4 分 F C DO D O B 17．（1）如图所示································ ································ ························ 2 分 y 4 3 2 1 –4 –3 –2 –1 O –1 3 4 x –2 –3 –4 （2） ( 1 , 0 ) 1 22 1 2 ································ ································ ························ 3 分 x ? 1 2  ································ ································ ··························· 4 分 18．（1）如图所示································ ································ ························ 2 分 DCA D C A （2）解：如图所示，过点C 作CH ? AB 于 H ，记 AD 与CE 相交于点 F , CH 2 ? BH 2∵ ?CHE ? ?CHB ? 90 ， CH ? 4 ， EH ? 8 ， CH 2 ? BH 2 EH 2 ? EH 2 ? CH 2 ∵ BE ?10 ， ∴ CE2 ? BC2 ? BE2 . ? 4 5 ， BC ? ? 2 5. DCFAH∴ ?BCE ? 90 . ······················· 3 D C F A H ∵四边形 ABCD 是平行四边形， ∴ AD∥BC . ∴ ?AFE ? 90? . E B ∴ AD ? CE . ······························· 4 分解：由题意，甲的边长为 80 180 5 ? 4 5 cm. ································ ······················ 1 分 乙的边长为 ? 6 cm 2 分 55甲与乙的边长和为6 ? 4 5 5 ?10 ? cm. 550040050062559∵ 20 ? ? ? ? 25 ， 6 ? 6? ?18 ? 20 , ························· 3 分 5 500 400