FdText数学3年：中学・塾用教材】 …

1 fdtext 3 [ ] 2 (1) (2) C (3) AB (4) [ ] (1) (2) (3) (4) [ ] (1) O (2) E (3) GH (4) ABCD GHEF [ ] 2 (1) (2) [ ] (1) (2) [ ] (1) B ABCD EBFG (2) O ABC DEF - 1 - [ ] [ ] [ ] 3 2 2 [ ] - 2 - - 3 - [ ] 1) 2) 3) 4) 5) [ ] 1) AOB DOC 2 2) ABC ADE 2 3) ADE ACB 2 4) ABO CDO 2 5) ABC DBA 2 (2 )

2 [ ] AB 6cm AC 9cm AD 4cm ABC ADB [ ] [ ] ABC ADB , A AB AC AD AB 2 3 2 ABC ADB [ ] AB 4cm AC 8cm AD 2cm ABC ADB [ ] - 4 - [ ] ABC ADB A AC AB AB AD 2 1 2 ABC ADB [ ] AO 2CO DO 2BO AOD COB [ ] [ ] AOD COB AOD COB AO CO DO BO 2 1 2 AOD COB - 5 - (2 ) [ ] AD 4cm DB 6cm AE 5cm ABC AED (1) ABC AED (2) EC [ ] (1) (2) [ ] (1) ABC AED A ABC AED 2 ABC AED (2) 3cm [ ] AC 6cm AB 7cm BC 5cm BE 3cm ACB AED DE [ ] - 6 - [ ] 103cm [ ] CAD CBE AC 12cm AD 9cm BC 10cm (1) ACD BCE (2) BE [ ] (1) (2) [ ] (1) ACD BCE C CAD CBE 2 ACD BCE (2) - 7 - (2 ) [ ] AC DE (1) ABC DBE (2) x [ ] (1) (2) [ ] (1) ABC DBE B AC DE BAC BDE 2 ABC DBE (2) 258 [ ] AB CD AB 6cm AO 9cm BO 5cm CO 8cm (1) ABO DCO (2)

3 DO CD - 8 - - 9 - [ ] (1) (2) [ ] (1) ABO DCO AB CD ABO DCO BAO CDO 2 ABO DCO (2) DO CD (2 ) [ ] A BC AD (1) ABC DBA (2) ABD CAD (3) AB 4cm AC 3cm BC 5cm BD [ ] (1) (2) (3) [ ] (1) ABC DBA B BAC BDA 90 2 ABC DBA (2) ABD CAD ADB CDA 90 ABD BAD 90 CAD BAD 90 ABD CAD 2 ABD CAD (3) - 10 - [ ] A ABC BC E BC AB D AB 16cm AC 12cm BC 20cm (1) ABC EBD (2) DE [ ] (1) (2) [ ] (1) ABC EBD B BAC BED 90 2 ABC EBD (2)

4 [ ] ABC BEC EDC 90 ABE BED - 11 - [ ] [ ] ABE BED AEB BDE 90 BAE ABE 90 EBD ABE 90 BAE EBD 2 ABE BED [ ] A ABC A B C BP CQ ABP CAQ [ ] [ ] ABP CAQ APB CQA 90 - 12 - BAC 90 BAP CAQ 90 BAP ABP 90 ABP CAQ 2 ABP CAQ [ ] ABCD CD E BE C AD F ABF DFE [ ] [ ] ABF DFE BAF FDE 90 F C BFE 90 AFB EFD 90 AFB FBA 90 FBA EFD 2 ABF DFE - 13 - ( ) [ ] A 36 AB AC ABC B BD ABC BDC [ ] [ ] ABC BDC AB AC ABC ACB A 36 ABC ACB 72 BD B CBD 36 BAC DBC C 2 ABC BDC - 14 - [ ] ABC DF A E DBE ECF [ ] [ ] DBE ECF ABC B C 60 BED CEF 180 DEF 180 60 120 BED BDE 180 B 120 BDE CEF 2 DBE ECF [ ] ABC 1 9cm BP 3cm APQ 60 (1) ABP PCQ (2) AQ - 15 - - 16 - [ ] (1) (2) [ ] (1)

5 ABP PCQ ABP PCQ 60 APQ 60 APB CPQ 180 60 120 C 60 PQC CPQ 180 60 120 APB PQC 2 ABP PCQ (2) 7cm ( ) [ ] ABC A BC D AB AC BD CD [ ] [ ] ABE ACF BAE CAF AEB AFC 90 2 ABE ACF AB AC BE CF BDE CDF BDE CDF BED CFD 90 2 BDE CDF BE CF BD CD AB AC BD CD - 17 - [ ] ABC A BC D AB AC BD CD B A E AE AC [ ] [ ] AC AE ACE AEC 2 2 ACE ACE AEC BAC 2 CAD ACE CAD AD//EC AB AE BD CD AE AC AB AC BD CD - 18 - ( ) [ ] AC BD yx, (1) (2)

6 [ ] (1) (2) [ ] (1) x 6 (2) x 8 y 5 [ ] DE BC yx, (1) (2) (3) [ ] (1) (2) (3) [ ] (1) x 6 y 12 (2) x 4 (3) x 18 y 4 - 19 - [ ] nml,,x (1) (2) (3) [ ] (1) (2) (3) [ ] (1) x (2) x 6 (3) x 30 [ ] nml,,yx, (1) (2) (3) [ ] (1) (2) (3) [ ] 1) x 7 2) yx 3) x 9 y - 20 - [ ] AB 1 2 P [ ] [ ] - 21 - ( )

7 [ ] P AD BC AB PQ CD AB 8cm CD 12cm PQ [ ] [ ] 524cm [ ] AB CD EF x [ ] [ ] 518 x [ ] AB QP CD CD [ ] [ ] 12 - 22 - [ ] BD DC 2 3 AE ED 5 3 BF // DG FG AC [ ] [ ] FG AC 6 25 [ ] 4 A B C D ABE BCF CDG AB BC CD 1 3 E F G H AB EF AE 6cm AH 18cm CG [ ] [ ] CG 38cm - 23 - ( ) [ ] ABCD AD BC P Q AB CD PQ AD AD 8cm BC 18cm AP AB 2 5 PQ [ ] [ ] 12cm [ ] ABCD AD BC E F AB CD EF AD BE [ ] [ ] 15 [ ] AD 2cm BC 5cm AD BC ABCD E BC CD F EF cm [ ] [ ] 107cm - 24 - [ ] ABCD AD // BC AD BC BD AC P Q BC x AD PQ yyx, [ ] [ ] yx2121 - 25 - ( )

8 [ ] ABCD AB 2 3 E DE AC F AC G AF FG [ ] [ ] AF FG 4 3 [ ] ABCD AE ED 3 2 (1) AF FC (2) FO OC [ ] (1) (2) [ ] (1) 3 5 (2) 1 4 [ ] ABCD BF FC 3 2 BD 10cm BE [ ] [ ] - 26 - [ ] ABCD AB 2 3 E DE AC F ABCD AEF [ ] [ ] [ ] ABCD BE EC 2 1 ( DEF ) ( ABCD ) [ ] [ ] 1 5 [ ] AD BC ABCD AD 4cm BC 8cm ADE 6cm ABCD [ ] [ ] 54cm - 27 - ( ) [ ] ABC AB AC M N MN BC MN BC 1 2 [ ] [ ] AMN ABC A AM AB AN AC 1 2 2 AMN ABC MN BC 1 2 AMN ABC MN//BC - 28 - [ ] - 29 - ABC AB M M BC AC N AN NC [ ] [ ] AMN ABC A MN//BC AMN ABC 2 AMN ABC AM AB 1 2 AN AC 1 2 AN NC (3 )

9 [ ] ABC AB M BC 3 D E AE CM F MD 4cm AF [ ] [ ] 6cm [ ] F AB E D AC 3 FG BD [ ] [ ] - 30 - ( ) [ ] ABCD AB BC CD DA E F G H EFGH [ ] [ ] ABD AE EB AH HD BD//EH BD 2EH CBD BD//FG BD 2FG EH//FG EH FG 1 EFGH [ ] ABCD AD BC P Q AC BD R S PSQR - 31 - [ ] [ ] DAB DP PA DS SB AB//PS AB 2PS CAB AB//RQ AB 2RQ PS//RQ PS RQ 1 PSQR [ ] AB CD M N P AD BC BD PMN [ ] - 32 - - 33 - [ ]

10 DAB DM MA DP PB AB 2MP BCD CD 2NP AB CD MP NP PMN ( ) [ ] AD BC ABCD AB DC M N , MN 12(AD BC) , MN BC [ ] [ ] ADN ECN DN CN AND ENC AD//BE ADN ECN 1 ADN ECN AN EN AM BM MN//BE MN 12BE ADN ECN AD CE MN 12BE 12(CE BC) 12(AD BC) - 34 - [ ] AD BC ABCD AB DC M N x [ ] [ ] [ ] AD BC M N AB DC AD 8cm BC 12cm PQ [ ] [ ] 2cm [ ] AD BC M N AB DC P Q MN 3 AD 2cm BC [ ] [ ] 4cm - 35 - ( ) [ ] M N AB BC PQ MN [ ] [ ] 2 3 [ ] ABCD E AB F BC EF AC G AC DE H AC EG FH AG GH HC [ ] [ ] 2 3 1 - 36 - ( )