1 4-11 11 1- -- -1 11 1 PART 1 PART 1 PART 1 PART 1 1(1) (2) (3) 100 (1)19 (2)39 3 2

2 4-23+2+2+ +2+2=3+218=39(3)49 n (2)3+2(n-1)100n49.549 1-1101-2()()()()()18 1 2 3

3 4-3299 1 268 99=333 102=2033 1033=330108() () ()

4 4-4102+(33-2)8=2682-110 2 (1) 10 (2) n (3) 322 2-210 2 AC15 15 AB 31

101025 4-5()114 ()() 1 [6(1-1)] 6 6 6 [6(2-1)] 63 18 12[6(3-1)] 63+(12-6)2 30 18[6(4-1)] 63+(18-6)2 42

n 6(n-1) 63+[6(n-1)-6]2 12n-6n=10=1210-6=1143-1() () ()

()6 4-63 2 3-242 2 5 (1) 4 2 (2) 5 2 (3) 4 3 (4) 5 3 (5) m n (1)(4)(1) 9(2) 11(3) 13(4) 16(5) (1)(4)1mn+1m m n 7 4-7m(n+1)(m-1)m(n+1)- (m-1)=mn+14-1n 4-22 4 5250 1 250 S 171 701 702 703 704 705 706 707 708 1 2 3 4 5 6 7 8 16 15 14 13 12 11 10 90 1 2

8 4-817 18 19 20 21 22 23 2430 29 28 27 26 25

16 1 17116=1011706 5-1512701 1617 701 2 3 5-212345678910147 9 4-96(1) 3122130 (2) 45710 (3) 24816 (4) 14916 (1) 3948(2) 1419(3) 3264(4) 25366-1(1) 74574023(2) 536276-2(3) 9121827(4)12131415 1 2 104-10(1) (2) (3) 7(1) 37 (2) 4.22.5 (3) -8-3(4) 5 14(5) 3aa a (1) 7-3=41115(2) 2.5-4.2=-1.70.8-0.9(3) (-3)-(-8)=5-18-13(4) 5 14 3 14 533

= 811(5) a-3a=-2a-a-3a7-1(1) 11 (2) -4 255 14114-11(3) -33 (4) 2 8 (5) 3a-b2a+b ab 7-2-1-268140 1( 1)na a n d = +11a na nnd21a dnna 1( 1)na a n d = + 31a dnna (1) 1( 1)na a n d = + (2) ( )m na a m n d = + 8(1) 3410 (2) 11 -35-5(3) 17 175(4) 4523124-12(1)39(2)-3(3)-63(4)17(1)10 1(10 1) 3 9 4 39 a a d = + = + = (2)11 1(11 1) a a d = +35 5 10 d=+ 3 d = (3)17 1(17 1) a a d = +117 16 5 a = + 163 a= (4) 1( 1)na a n d = +52 4 ( 1) 3 n = + 17 n =8-11713 -18-2258na (1) 10 (2) 50na = n =97 6914 34(1)(2)(3)(1)99 (2)-5 (3)21 134-13(2)14 7(14 7) a a d = +34 69 7 d = + 5 d = (1) 7 1(7 1) a a d = +169 6 ( 5) a = + 199 a= (3) 0na16 ( 1) 32 800 n + >1252n >254-2526 16+(26-1)32=816 PART 4 PART 4 PART 4 PART 4 n 1 2 2 34 n n-1 n-2 n n-1 n-2 an= an-1+an-2a1=1a2=2a3=a1+a2a4=a3+a2Fibonacci SequencePART1PART1PART1PART1

2 4 6 8 10 1 3 5 7 9264-261-131 1a 4 14 a=2a 7 1 1 24 2 1 a = 3a 10 1 2 34 3 2 a= 104 10 9 31 a = =1-228 ()()3 ()()3 ()1+3(10-1)=28 2-1(1) 82 (2) 8n+2 (3) 40 2-280 3-170 10(25)6=703-240 10 105-10=404-1n+2 0 1 2n 2 3 4n+2 2274-274-2565-122 102+2=22 5-21478=1836-1(1) 6(2) 1 536 276-2(1) 39(2) 167-1(1) 110(2) -183(3) 9156 (4) 3 2 4 2 2 (5) a+3b5b-a+2b7-2-26 -26-1408140-(-1)=81-40(-1)-(-26)8-132 8-2(1)29 (2)179-11-1 219 (3) 39-2(1) -24 (2) 3 (3) 6 (4) 10 10-1-27116 7(16 7) a a d = +16 11 9 d= + 3 d= -2+3-4+5-6 284-28101 7(101 7)11 94 ( 3)271dddddada d = += + = 10-267d3 6(3 6) 5 3 a a d d = + = 9 6(9 6) 5 3 a a d d = + = + (5 3 ) : (5 3 ) 2: 3 d d+ =13d=9 12: (5 3 ) : (5 6 ) a a d d = + +(5 1) : (5 2) = + +6: 7 =11-14816 123 4da b ada b b+ = =

= = 11-284x-dxx+d(x-d)+x+(x+d)=180x=60(x+d)(x-d)=73 2x=5dd=25x=24 60+24=84294-2912-14812-242 10 2 3 10 23 4 14 3 4 14 2d d d da b a b a b aa b a b b+ + + = + = =

+ = + = =

4 a b =13-1160 2 a da da a d + 2 a d +2 3( 2 ) 8( 2 ) ( ) ( ) ( 2 ) (5 2) 180a d a da d a d a a d a d+ =

++ + + + + =

4 4 108108 26dd aa dda= =

= = =108+226=16013-2369 6-d66+d 100(6-d)+106+(6+d)=100(6+d)+106+(6-d)+594 d=-314-1(1)40 (2)36(1)ma nbm na b =13+(m-1)9=16+(n-1)n3m=4nmn m=4n=3304-3013+(4-1)9=40(2)9 12 14-2239PART2 PART2 PART2 PART2 1220 2 3454165 5-12642500798x=495 -5 101474-311 11 1- -- -2 22 2 PART 1 PART 1 PART 1 PART 1 n nn n 1Ex. 246810 246810 21a d 2 2a n na 1 2...na a a + + + nS 1 2 3...n nS a a a a = + + + +3n n 1a n na n 211 3...( )2nnnS a a a aa a n= + + + + =+ n 1a d 1[2 ( 1) ]2na n dSn + = []1( )2nna a nS+ = 1( 1)na a n d = + 1 1 1[ ( 1) ] [2 ( 1) ]2 2na a n d n nSa d n + + + = =4-321(1) 31(-1)(-13)(2) -8219 (3) 30 100-16(1) -45(2) 190(3) 12604(1) 13 a= 2 d = 1( 1)na a n d = + 13 3 ( 1) ( 2) n = + 9 n =9[3 ( 13)] 9452S+ = = (2)19[2 ( 8) (19 1) 2] 191902S + = =(3)30[100 ( 16)] 3012602S+ = =30 1(30 1) a a d = + 16 100 29 d = + 4 d =1-18 34 71-279410794-33210 1000 3 330 1668151299931( 1)na a n d = + 999 12 ( 1) 3 n = + 330 n =330(12 999) 3301668152S+ = =2-1100 1000 3 2 2-212345100 2 3 33 120 18 17 ...4 2+ + + n 11622n 13 20 n ordn d = = 4-34120 a= 3 118 20 14 4d = = 1[2 ( 1) ]2na n d nS+ =1[2 20 ( 1) ( 1 )]141622 2n n + =5 5325 [40 ]4 4n n = +233 260 0 n n + =( 13)( 20) 0 n n =13 20 n o d rdn= =3-1(-25)(-22.5)(-20)n -135n 3-21234n 1275n43 711 151923 (1) (2) (1) 839(2) 160204-35(1) 1 2 3 20 210 371115210 20[2 1 (20 1) 1] 201 2 3 ... 2102a + + + + + = =2103 (210 1) 4 839 b= + =(2) 19[2 1 (19 1) 1] 191 2 3 ... 1902a + + + + + = =1913 (191 1) 4 763 b= + =191 192 210[763 839] 20... 160202+ + + + = = b b b4-1101112131415100 4-21223334444400 n nn n 1 n 0na s 2 n 0na > 4-365( ) 300 3 f n n = n (1) (1) (2) ... ( ) f f f n + + + n =(2) (1) n =99 or 100(2) 14850(1) ( ) 300 3 f n n = (1) (2) (3) ... f f f > > >(1) (2) ... ( ) f f f n + + + ( ) f n 00( ) 0 f n s300 3 0 n s100 n > 100 n = ( ) 0 f n = n 99 or 100(2) [ (1) (100)] 100 (297 0) 100148502 2f f + + = = =5-1-4017 -28(1) (2) 1 5-23 66 12n 200 n 4-37 1 n nS 1 2 1...n n nS a a a a= + + + + 1 1 2 1...n nS a a a = + + + 1 n n na S S = 2 2 1 n + n 1 n + a d ( ) .. ( ) [ ( 1) . ( ) ] ... ( ) a nd a n d a a d a nd d a + + + + + + + + +(2 1) n a = + =3 n n d 2 1a a d = 4 3a a d = 1 n na a d = 2nd 4 a bm( )( 2)2a b m + +m ( )2a b m +615 -25514 -21715 15 -384-3(1) 15255 S = 14217 S = 15 15 14255 ( 217) 38 a S S = = = 4-38(2) 1 1515( ) 152a aS+ =1( 38) 152552a = 14 a=(3) 15 1(15 1) a a d = + 38 4 14 d = + 3 d = 6-120 -47019 -41816 6-2n 22n n 8 30 713 31 133(1) 22 (2) 18 26 (1) 7(2) 63(1) 13 31 22 133==(31-13+1)22a

22a =7(2) 18 26 22 4-39=(26-18+1)22a =637-135 18 287-220 -10108(1) n (2n+3)(3n+2)11 (2) n (2n+3)(3n+2)11 (1)34(2)913(1)1a d 1a'd'1 111 11(2 10 ) 11 (2 10 ) 11: :2 2a d a dS S'' + + ' =1 1( 5 ) : ( 5 ) a d a d'' = + +4-406 6: 3: 4 a a '= =(2)11 11: a a '11 10 11 10( ) : ( ) S S S S' '= 1 1 1 1(2 10 ) 11 (2 9 ) 10 (2 10 ) 11 (2 9 ) 10[ ]:[ ]2 2 2 2a d a d a d a d' '' ' + + + + = 1 12 20 2 20( ) : ( )2 2a d a d'' + +=1 1(2 20 ) ( 21 2 2 20:2 21 ) a d a d'' + = +21 21: S S '=(2 21 3) : (3 21 2) = + +9:13 =11 11 1 1: ( 10 ) : ( 10 ) a a a d a d' '' = + +1 1(2 20 ) : (2 20 ) a d a d'' = + +1 1(2 20 ) 21 (2 20 ) 21:2 2a d a d'' + + =21 21: 9:13 S S '= =8-1n (n+7)(3n-2)1[2 ( 1) ]2na n d nS+ =21 4-4115 8-2n (3n+1)(7n-11)7 940 4 181 (1) (2) (3) 100 (4) (1) 25(2) 101 (3) 21 (4) 4120 (1) 40181 a = 4 d =40 1(40 1) a a d = + 1181 39 4 a = + 125 a=(2)20 1(20 1) a a d = + 25 19 4101= + =(3) n 100 4-42100na >1( 1) 100 a n d + >25 ( 1) 4 100 n + >3194n > 100 4020121 (4)40(25 181) 4041202S+ = =9-13 362 9-210 20 25 10100 10 5 4-435 110 a= 5 d = 100nS = n 1[2 ( 1) ]2na n d nS+ =[2 10 ( 1) 5]1002n n + =23 40 0 n n + =( 8)( 5) 0 n n + =5 8 n or d dn = = ()10-1n 312 3 7 n=10-254 5825654545PART 2 PART 2 PART 2 PART 2 121 3 5 ... 46 a + + + + = a =21 3 5 7 ... (2 1) n + + + + + 3 12 17 5 4-44134 5 100 3 511 -1011 2310 6nS n 1080 S = 20180 S = 30? S =730 300 3 81a 1a 1b 2b 117 a= 193 b= 100 100110 a b + = 1 1a b + 2 2a b + ...100 9381353 11 y11 161151 271252491454 5101555y 10na 1 2 35 a a a + + =3 4 535 a a a + + = 16 17 25... ? a a a + + + =11n (3n+7)(7n-3)5 124-45 1 23 456 78910 (1) (2) 131 2 4 5 7 8 10 11 299...3 3 3 3 3 3 3 3 3+ + + + + + + + + PART 3: PART 3: PART 3: PART 3: 12n n1 3n 1841[2 ( 1) ]2+ =na n d nS12 a=31( )8n n nS S S =

38n n nS S S =

39n nS S =9 [2 2 ( 1) ] [2 2 (3 1) ] (3)2 2n d n n d n + + =2 236 9 9 12 9 3 n n d nd n n d nd + = + 0 n = Q 4 d =4-4626 10 9511 17 21715 31 15 31 8331a d10 517 1095217S SS S = =

1 11 1(2 9 ) 10 (2 4 ) 5952 2(2 16 ) 17 (2 9 ) 102172 2+ + =+ + =a d a da d a d

117 1913 31a da d+ =+ =

152ad==31 14(2 5 30 2) 31 (2 5 13 2) 148332 2S S + + = =31213214321225 225 71 21 321 4321 225 1 n + ( 1)2252n n + BAD13(1) BAC (2) DAE (3)1 (4) CAE ECABD14-196(1)AC AB = ()(2)BC ()(3)BAHCAH ( AH A )(4)CH BH = AH BC( AH BC )(5) ABC AH BHABHAC(B) BHA4-1979. ABC AC AB = (BC) ABC ACB AC AB =AAAB AC = ABC ACB (SAS )BCA BC BC AB AC CBAB CAC BA4-19810. ABC BC AC AB = ABC ACB BCCB BC =CB ABC ACB (ASA ) AC AB =CBAAC BAB C4-19910-1.()L BC P L PC PB =10-2.() PB PA = P BC (MBC PM BC )L90 90 MBCPBCP4-20010-3.()BC BC LBC BC21PQPQPQBC L10-4.()L BPC Q L PB QBB PC QCC QC QB =QPBCL90 90 CBPQ4-20110-5.() PB QBB PC QCC PQBPC 10-6.()PP PQBPC 90 90 CBPQQCBPP4-202PART 21.() (A) SSA(B) AAS(C) SAS(D) SSS2.()ABC AC AB = ADCAEBABEACD (A)ASA (B)AAS (C)ASA (D)AAS AC AB = ADCAEBAAABE ACD ABCDE4-2033.()ABC DEFADBEAB (2x3)BC (4x2)AC 3xDF (x8)(A) x2 (B) x3 (C) x4 (D) x54.BACDCAACBCADADBC OOABOCD90AB 12OB 13AD5.(A) (B)(C) (D)ABCDO 12 13 4-204PART 31.()ABC DEF (A) AEBFBC DE(B) AFAB EF AC DF(C)AB DF BC DE AC EF(D) AE90AB DE BC DF2.() A BC DCE(A) 120(B) 135(C) 150(D) 165CEB AD4-2053.() 5 . 3 = = AD AB 5 . 3 = = BD BC BDC(A) 15 (B)30 (C) 45 (D) 604.ABCD EF AB CDAG ABG A BGB EF BAB 5. ()4.AB 3 AG(A) 2(B) 3 (C) 233 (D) 2 3GB' F ECADBCDAB4-2066.()ABC BC AC AB < < A90BC PPE AB E PF AC F PF PE = (A)BC LL BC PP (B)AC MMBC PP (C)A NN BC PP (D)A BC KK BC PP 7.()AB 4ABP30CBPAC ABCABC30 (A)AC 2 (B)AC 3 (C)AC 4 (D)AC 5 30 4ABPBCA4-207PART 41967 200 (60 )250 () SSS4-2084 4 (1991)75~784-209PART 11. (1) 60 (2) 10(3) 5 32. SSS 3-1. 3-2. 30ABC30ACCB4-2106-1. 6-2. 8. (1) 60 (2) 60 (3) 47 (4) 1390A4B5C90AB4C54-21110-1.~10-6. PART 21. (A)2. (D)3. (C)4. 185. ( C) PART 31. (A)2. (D)3. (B)4. 60 5. (A)6. (C)7. (B) 4-212 3-4 PART 1 SSS SSS 123~1. 3214-213 A C acbbcaabc( a BC = b AC = c AB = )(3 )1. (1) 234 (2) 4610 (3) 345 (4) 11100 (5) 1100100(6 ) 100100100 cbaA()C()B()4-2143 345 5453 345(534543)1100100 1100100 (1001001 )cacb(abc 0) cab cba abc 4-2152. 37xx x 37x7x3 (73 )3x737xx37x10 3x7x734x 4x10 x 567892.x x (x37)x x (x73)4-2162. (1) 732 (2) 733(3) 734 (4) 734.5 (5) 735 (6) 739(7) 739.5(8) 7310 (9) 7310.5(10) 7311 (3)(7)6 12 (9 ) (1 15 )4-21773 (6 )73 (12 )()4-218ABC AC AB = BCABC BC AC AB = 3. ABC ADC AC AD > ADACDACB AC ADCABC (why)ACDADC B CAB CAD4-2193. AC AB = ABCADC 4. B CAD4-220 ABC ABC DBC DBCDCB DBC DC ( AC DA+ )DCB DBADB AB DA+ DB AC AB = AC DA+ DB DC DBDB CA4-221PART 21.23456 abc abc 2.37aa 3.()ABC AB90AB ABC(A) (B)(C) (D)4.()ABC ABC(A)A58 (B)B60 (C)C62 (D)B904-2225.()ABC A50B65(A)AC BC (B)BC AC = (C)AB BC (D)AB BC 6.()ABC AB7BC8CA2.5 ABC 4-223PART 31.abc abc8 c 2.()(A) (B)(C) (D)3.()ABC A70B60 200 = AB (A) 200AC BC (B)BC AC 200 (C)BC AC 200(D) 200AC BC4.()ABC ABB 120BC AC AB (1)ABC (2)AC D AD AB = 3.14 DB DC = 3.14 4-2245.()A AXY AB AB M(A) MXY (B) MBY Y B (C) MXY X Y (D) MXY Y X 120 25 35 XYA(B)4-225PART 4(2003) 4-22620ABC BA AC AD =ACD ADCACD BCDACDADC BCD BCDADC BD>BC () AD BA+ >BC AC AD = AC BA+ >BC + AB BC > AC CB AC + > ABBCADBCA4-227[1](2003)()-72~73[2](1992)-[3](2005)~1~78[4] David E. Joyce (Professor of Mathematics and Computer Science Clark University)Book IEuclid's ElementsMathematics web pageshttp://aleph0.clarku.edu/~djoyce/java/elements/elements.html4-228PART 11. (1)(2)(3)(4)(5)(6) 2. (1)(2)(3)(4)(5)(6)(7) (8)(9)(10) PART 21. 72. 4a103. (C)4. (B)5. (C) 6.ABCPART 31. 32. (D)3. (B)4.AB AC BC > >5. (D)AB YB XY AX + + AXY XY AB M()M B Y X A4-229 4-1 PART 1 L1L2L1L24-230(1)L1 LL2 LL1L2L1// L2L1L2M()(2)LL1L2M LL1L24-231(1)L L1L(2)L L2L()LL1L290 90 90 4-2321. (1) (2) (1)(2)L1L2L1L2L1L24-233L L1L2L L1L2~L L1L2L1L2LL1L2L1LL2>90 90 4-234L1L2L L L L14 1234L L24 56788 L L1(1234)L L2(5678)1234 L L1()1LL1L2876 54321LL1L2514-2355678 L L2()51515 26 26 37 37 48 48 4 15263748LL1L262LL1L273LL1L2 844-2368 3456 4 L1L235 L ()35 46 L ()46 36 L 36 LL1L26354LL1L235LL1L264LL1L2634-23745 L1//L24 152637482 35462 3645LL1L254L1LL2872163544-2382. (1)4 (2)2 (3)2 (1)4 15263748(2)2 3546(3)2 36452. (1)4 15 (2)2 35(3)2 36LL1L287216354L2LL1872163544-2393. L1L2L 1212 12180255122 1 ()2 A L2A LL1L2 21LL1L2 21A4-240L1L2C 1 ABC 12330123.121 2 1802551 2 253251 2 3 1231231230303 L1L2L1L230 L1L23 0 L1L2L 12 LL1L2321BCA4-241L1L2(L1L2)12L1L2(L1L2)12 L1L2()123-1. 3.3 3.12LL1L2 21L1LL2 21BALL1L221345678L1L2()124-2423142 ()3 4 ()5180161802 (180) 5 6 ()7180181802 (180) 7 8 ()3-2. 123142 () 12 ()3 4 ()5180161802 (180) 5 6 ()L1LL2213456784-2437180181802 (180) 7 8 ()4. L1L2L L1//L2(12 ) L PP M L1 L1//L2ML2L1LL2 21BAML1LL2 90 90 21RQBAP4-244APQ 1APQ90BPR 2BPR901APQ2BPR 12 ( APQBPR() )3 4-1. L1L2L L1//L21552 3 4 5 6 7 8 L1LL2876543214-24512553 34555612578125(1255)2557125 (27180)3556125 (36180)255355 (23) 61257125 (67) L1LL2876543214-2464-2. L1L2L L1L2()1802553 4 5 6 7 8 1802553 38045551006125710081252557100 (27155180)3806125 (36205180)LL1L221345678L1LL2876543214-247255380 (23) 61257100 (67) 5. L1L2L L1//L2(2718036180)L1LL2876543214-248 L PP M L1 L1//L2ML2ABRQ 279090180271803180761802 (180)36(1807)(1802) 360(27)180L1//L21217180 (180)2718013 () 12233626180ML1LL290 90 87654321RQBAPL1LL2876543214-2495. L1L2L L1//L2(2367) L1//L21213 ()2361802718011267L1LL287654321L1LL2876543214-250(1)(2)(3)4-251()()4-2526. L1L2L ML1L2 L PP M L1AQP90M3APQ 1APQ90BPR 2BPR3180APQBPR ()12 ()1APQ2BPR90 (2BPR)3180390M L2ML1L2L1// L2L1LL2 21BAML1LL290 21RQBAP34-253(1)(2)A A 7. 4-254 36180 ()26180 (180)2313 ()12 () L1// L2L1// L2LL1L2876543214-2558. 23 ()13 ()2312 () L1// L2L1// L2LL1L2876543214-256 L1L2(1)L1L2()(2)(3)(4)L1L2L1L24-257PART 21.()ABC 8 DBC 8 DBC = 20CAD = 50 AED =(A) 70 (B) 100(C) 110 (D) 1202.()T L1L2 1 2 3 4 (A) (B) (C) (D)1234L1L2T1 3 2 3 2 4 3 4 5020ECDBA4-2583.()L1L2L 161260L1L2()(A)L1L2L ()59(B)L1L2L ()1(C)L1L2L ()59(D)L1L2L ()14.() BF CD AE // // CG AB DH // // ABCD(A) 180(B) 270(C) 360(D) 450L2LL121 A EDBCFGH4-2595.(1)L1L2L 12 1255 (2)L1L2L 12 1290 (3) ()(1)&(2)(A)1255L1L2(B)1290L1L2(C)12125L1L2(D)L1L24-260PART 31.()L M()(A) L M()1 (B) L M()2 (C) L M()1 (D) L M()2 2.()ABCDB120D50PCRPRC C AB P C // AD R C //A(A) 80(B) 85(C) 95(D) 11030313233LM 50 120 RABCDPC'4-2613.()L 1L 2L 1 2 1 3 1 2 3 (A) (B) (C) (D) 4.()L1L2L L1//L2180260BF DBCBF AE (A)BF AE (B)BF AE ()5(C)BF AE ()10(D)BF AE ()15L1LL221ABCDEF4-2625.()AB //CD142(A)(B)(C)(D)4321FEBACD CF AE // EF4-263PART 4L1L2L L1L ABCD(1234)L1L2L 5678L2()3 4 A5B6C7D82 C5D62 C6D5L1L2LL1L28765DCBA4-2644 A5 B6C7 D8FL1L2L5AL1L2L6BL1L2L7CL1L2L8D4-2652 C5 D6U2 C6 D5Z L1L2L5CL1L2L6DL1L2L6CL2L1L5D4-266PART 12. (1)4 15263748(2)2 3546(3)2 36453-1.3-2.4-1.255355455 51256125712581254-2.380455 51006125710081255.4-267PART 21. (C)2. (D)3. (B)4. (C) 5. (1)(2)(3) (C) PART 31. (D)2. (C)3. (B)4. (C)5. (A) L1LL21=2=55 21L1LL21=2=90 214-268 4-2 PART 1 ABCDABCD4-26936090() AB AD AB BC BC AD// DC AB// 90()CABDCABD4-270()CBDA4-2711. ABCD DA CD BC AB = = = BD (1)ABDCBD (2)AC(3)1234(4)ADBC AB DC (1)~(3)(1)ABD CBD BC AB = CD AD = () BD BD = ()ABDCBD (SSS )4321BDAC4-272(2)ABDCBDAC1234(3) AD AB = ABD 13(2)12341234(4)AB CDBD 14 14 () DC AB//23 () BC AD//41CBDA32CBDA4-273 ()4-274()()4-275() () () () () ()4-2762. A130B50C130D50DAB CDAB C4-2772. ABCD ACBD3. ABCD ACBDDAB CDAB C4-278 ADBC AB AB AD// BC AB180 ()CD180AD180 BC180AB180AD BDAB180BC ACDAB CDAB CDAB CDAB C4-2793. ABCDEFGD B35 (1)D (2)F (3)FGD (4)FED 4. 35 GDAB CEFDAB C4-280 C AB CD AB =B AD BC AD =ABCD CD AB = BC AD = D AB CD AB CD AB C4-2815. ABCD (1)BD(2)AB CD(3)BD(4)ABDCDB(AB CDADCB)(5)ABDCDB (1)&(2) D AB CD AB C4-282(3) (4)&(5) ABCD BDABD

CDBAB CDADCBABCD ACABDCDBADBCBD ABDCBDABCADBCDBADC ABCADC ACABCD DB CD ABD ABB CDD AB C4-2835-1. 5.ACABCD ABC

CDA ABCD BDABD

CDBBDD AB CD AB CD AB C4-284AB DC BD12 AB // DC12ADBC BD34 AD// BC34ABD CDB 12BDBD34ABD

CDB (ASA )D AB C12D AB C34DB CD ABD ABB CD123414234-285(1)AB // DC AD// BC(2)ACBD(3)AB CDADCBDABCDAB CD AB C4-2865-2. x y ()x y2x 10 3xyODABC4-287 CO AO = DO BOBDAC AC BDBDAC BDAC ()OACBDOACBD4-2886.6. ABCD AC BDO O AC ( CO AO = ) O BD( DO BO = )OACBDODABC4-289 AOB COD DC AB// 34 ()ABCD CD AB = ()12 ()AOB

COD (AAS ) CO AO = DO BO =ODABC1234 4-2906-1. ABCD AC BDO O AC ( CO AO = ) O BD( DO BO = )()AOD COB BC AD// ()ABCD () ()AOD

COB (AAS ) CO AO = DO BO =ODABC 1234ODABC4-291AOB AOD AO AO = AOBAODOD OB = AOB AOD AOBAOD AOBAOD AD AB