2012年福州市初中毕业班质量检查数学试卷参考答案及评分标准.doc

2012年福州市初中毕业班质量检查 数学试卷参考答案及评分标准 ?1．A??2．B??3．C??4．C??5．D??6．A??7．D??8．A??9．B??10．C 二、填空题： 11．????12．8?????13．????14.1????15．3 三、解答题： 16．（1）解： ??????=?·················································································?4分 ??????=. ·······································································································?7分 2）解： ??????=?···················································································?4分 ??????=, ····································································································?5分 当时，原式==5．·························································?7分 17．（1）证明：∵AB与CD是平行四边形ABCD的对边， ∴AB∥CD，·······················································································?2分 ∴∠F=∠FAB．····················································································?4分 ∵E是BC的中点，?∴BE=CE,·····························································?5分 又∵?∠AEB=∠FEC，?·······································································?6分 ∴?△ABE≌△FCE．···········································································?7分 a?= 45°，β= 60°，AD＝80． 在Rt△ADB中, ∵，? ∴．············?2分 Rt△ADC中, ∵, ??????∴．·······?5分 答：这栋楼高约为218.6m．??··················?7分 181）=???25???%，90o?．···········································································?2分 ????补全条形图.·····································································································?4分 2）众数是5，中位数是5．··········································································?8分 3）该市初一学生第一学期社会实践活动时间不少于5天的人数约是： （人）．···············································?12分 191）证法一：连接AE,?··································?1分 AC为⊙O的直径, ∴∠AEC=90o,即AE⊥BC.?····························?4分 AB=AC, ∴BE=CE，即点E为BC的中点．················?6分 OE，?·····································?1分 OE=OC, ∴∠C=∠OEC. ∵AB=AC, ∴∠C=∠B, ∴∠B=∠OEC, ∴OE∥AB.?················································?4分 , ∴EC=BE,即点E为BC的中点. ··················?6分 COD=80o, ∴∠D