1、 2017 2018 90 120 4 10 40 1 4 A B C D 2 A 2cm 3cm 5cm B 5cm 6cm 10cm C 1cm 1cm 3cm D 3cm 4cm 9cm 3 A B C D 5 4 A B C D 5 ABC AB=AC D BC A B= C B AD BC C AD BAC D AB=2BD 6 BFD A B C D 6 7 ABC BD ABC P BD AD=6 CP A 3 B 3.5 C 4 D 4.5 8 ABC AB AC D AC=5cm BC=4cm DBC ( ) A 6 cm B 7 cm C 8 cm D 9 cm 7 8 1
2、0 9 A B C 90 D 10 ABC AB=AC CD AB D DCB A B C D 4 10 40 11 50 _ 12. 2 7 x x . 13 _ 14 1 2 3 4 14 15. D BC E AC S ADE=2 S ABC=_ 16. BDC= BOC= 17 D BC AB=AD C= E BAD= CAE 1+ ABC 16 17 18 ABC A BC D BC=12cm CD BD=1 2 D AB cm 19 ABC AB=AC AB DE AC E D ABE EBC=2 1 A= 18 19 20 6 5 . 5 40 21. 6 A B 22. 12 ABC A 0 2 B 2 4 C 4 1 1 ABC y A1B1C1 2 A1B1C1 3 ABC 23. 8 A D F B AD=BF AE=BC EF=DC CD EF 24. 8 AB=AC DB=DC P AD ABP= ACP 25. 6 RT ABC BAC=90 AC=2AB D AC 45 A,D BE EC BE EC
