1、 2017-2018 1 6: BABBCA 7 12 BCCBDD. 13. 35 14. 15. 15cm 18cm 16. 4 17. 4 3 2 3 4 3 18. 1 4 19. ABC AD BAC DAC= ADC= C D 20. 1 1 AB AB l P P 2 2 A l l M M 21. DE BC DOB= OBC BO ABC DBO= OBC DBO= DOB BD=OD OE=EC ADE =AD+OD+OE+AE=AD+BD +AE+EC=AB+AC=14cm 22. BF=EC BF+CF=EC+CF BC=EF ABC DEF ABC DEF SAS 1
2、= 2 23. BE ED BC Rt ABE Rt DBE ABE DBE HL DE=AE DE+CE=AC 24. 4 5 6 7 8 1 2 3 4 5 2 5 9 14 20 1 2 n n 3 n n 3 3 = =35 25. AC=2AB D AC CD=AB AED AE=DE EAD= BAE= ABE DCE ABE DCE SAS BE=CE AEB= DEC BED+ DEC= AEB+ BED= BE CE BE CE 26. 1 CE=BD Rt ABC Rt ADE AE=AD AC=AB EAC DAB EAC DAB SAS CE=BD 2 EAC DAB ECA= DBA ECA+ CBF= DBA+ ECA+ CBF+ + 3 Rt ABC Rt ADE AE=AD AC=AB EAD= BAC EAD+ DAC= BAC+ DAC EAC= DAB EAC DAB SAS CE=BD EAC DAB ECA= DBA ECA+ CBF= DBA+ ECA+ CBF+ A +
