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ᇏ࿐ඔ࿐ᄖᆽ         2019 ୍ֻ 8 ௹                                   ZHONGXUESHUXUEZAZHI


            3   ࢳีႋႨ                                           ဢđ ೂ ͇ “ ࡃ϶࢘ ”、“೘Լᆰ”……đ С൳ܼնഽള֥ᇗ
                ২ 1   ೂ๭ 7đ ਫྙ ABCD ֥шӉູ 4đ ∠A = 60°đ          ൪．୍ུ࣍đ ྸ؟၂ཌ࢝ഽమྏႿଁี࿹࣮đ Ⴟ൞Ӂള
            E ൞ш AD ֥ᇏׄđF ൞ш AB ഈ֥၂۱׮ׄđ ࡼ EF ಡ                 ၂ն஻ଽݤپڶ、 ຓ࿼؟ົ֥൫ีđ бೂ “ޱ҂݂”、
            ׄ E ୉ൈᆌ࿈ሇ60° ֤֞ EGđ ৵ࢤ GBđGCđ ᄵ GB + GC           “ έ൦ჵ”…… ݺีေቓđ ۷ေ࿹࣮đ ೂޅൌീ࢝࿐္
            ֥ቋཬᆴູ             ．                                ᇀܱᇗေ．“ ᆩఃಖ” ა “ ᆩః෮ၛಖ”ѩईđ Ҍି۷ധ

                                                               ҪՑ֥৘ࢳඔ࿐đ ငࢸބනਫ਼Ҍି۷ູܼখ．
                                                                  “ ඔ࿐ࢳีଆ྘൞ڎླေ࢝”൞֒భ၂ཌ࢝ഽ௴
                                                               ђܱᇿ֥໙ี．ᆭ෮ၛ࣯ࢲᆃ۱໙ีđ гᆀಪູ “ඔ࿐
                                                               ࢳีଆ྘” Ⴕఃࡎᆴđ ႻႵఃр؊．ఃр؊͇ ࢳีଆ྘
                                                               สਫ਼߄ đ“่ࡱّഝ”ൔ֥קཟනົཋᇅਔ࿐ള֥ؿ

                      ๭ 7                    ๭ 8               ೛නົ．หљ൞đ ೂݔ҂ᇿᇗ “ඔ࿐ࢳีଆ྘”֥ݖӱ
                                                               ߄࢝࿐đ ࠏֹྀ “ଆ྘߄”ࢳี߶֝ᇁනົٚන֥ࡺ
                ٳ༅აࢳ       ೂ๭8đ Ⴎܨ׸ჰ৘ၞᆩđ ׄ G ᄝ၂่
                                                               ߄．бೂ༯૫၂২͇
            ཌ؍ഈᄎ׮đ ః݅ࠖॖၛᆃဢಒק͇ ݖקׄ E ཟᇶ׮
                                                                   ೂ๭ 11đ ⊙O ֥϶ࣥ൞ 2đ ׄ M ູ϶ࣥ OA ֥ᇏׄđ
            ֥ׄᄎ׮ਫ਼ࣥ ——— קཌ̵ ؍̶ AB ቔԼཌ؍ EH̵ ҂э
                                                               ׄ B ູ ⊙O ഈ֥၂۱׮ׄđCM ⊥ BM ࢌ ⊙O Ⴟׄ Cđ
            ਈ̶ đ ࡼ EH ಡׄ E ୉ൈᆌ࿈ሇ 60° ֤֞ EH'đ ݖ H' ቔ
                                                               ၛ BMđCM ູшቔइྙ BMCNđ ౰ MN ֥ቋཬᆴ．
            EH' ֥Լཌࢌ ABđCD Ⴟ MđNđ ཌ؍ MN ູࠧՖ׮ׄ G
            ֥ᄎ׮ਫ̵਼ࣥ ൌ࠽ഈđ ಒקՖ׮֥ׄఏׄ M აᇔׄ N
            ࣼॖၛಒקਔ̶ ．Ֆط౰ࢳ “GB + GC ֥ቋཬᆴ”ൌᇉ
            ഈ൞ “ ࡼफႂઔ” ໙ี．
                หљֹđ ׄ B ܱႿ MN ֥ؓӫׄఞݺ൞ׄ Eđ“GB
            + GC ֥ቋཬᆴ” ູࠧ “CE ֥Ӊ”đ △CDE ᇏđCE = 2đ
            CD = 4đ ∠D = 120°đ ॖ౰ CE = 2 7 ．Վԩ҂ᄜሕඍ．                      ๭ 11                 ๭ 12
                                        槡
                                           2 5 đO ൞ BC ш֥
                ২ 2   ೂ๭ 9đ ᆞٚྙ֥шӉູ 槡                              ౰ࢳൈđ ޓಸၞ߶ྙӮᆃဢ֥ܸྟ͇ ၛ “M ູק
            ᇏׄđ ׄ E ൞ᆞٚྙଽ၂ׄđ ౏ OE = 2đ ࡼཌ؍ DE ಡ                ׄđB ൞ᇶ׮ׄđC ൞Ֆ׮ׄ” Ⴈ “ ܨ׸ჰ৘” ฐ౰ׄ N
            ׄ D ୉ൈᆌ࿈ሇ 90° ֤֞ DFđ ৵ࢤ OFđ ᄵ OF ֥ቋཬ               ֥݅ࠖđ ࣉط౰ࢳ MN ֥ቋཬᆴ．
            ᆴູ          ．                                          ൙ൌഈđ ᆃ৚ᅼཌ؍ BMN ֥ࡃ࢘҂൞ק̵࢘ ౼ࠫ
                                                               ᇕ҂๝֥౦ྙࣼॖܴҳ̶֞ đ ္ႮՎॖᆩ MN ა BM ҂
                                                               ູקбđ ܣ҂ି൐Ⴈ “ ܨ׸ჰ৘”．
                                                                   ҂ݖđ ׄ N ֥݅ࠖಒൌ൞ჵđ ೂ๭ 12đ ࠎႿइྙ֥
                                                               ၂۱ྟᇉđ ֤ ON + OM = OB + OC đ ՖطđON = 7 đ
                                                                             2
                                                                                              2
                                                                                        2
                                                                                   2
                                                                                                         槡
                                                               Ⴟ൞đ ׄ N ֥݅ࠖ൞ၛ O ູჵྏđ7 ູ϶֥ࣥჵđ ࣉ
                                                                                            槡
                      ๭ 9               ๭ 10
                                                                                7 －1．
                                                               طđMN ֥ቋཬᆴູ 槡
                ٳ༅აࢳ       ೂ๭ 10đ Ⴎܨ׸ჰ৘ၞᆩđ ׄ F ᄝ၂                  ֌҂ॖڎಪ đ“ ඔ࿐ࢳีଆ྘” ֥ႋႨྟᆴ֤ᄝ࢝
            ่޶ഈᄎ׮đ ః݅ࠖॖၛᆃဢಒק͇ ৵ࢤקׄ D აᇶ                        ࿐ᇏ຋ड͇ ᆃུ “ ඔ࿐໙ีଆ྘” ିϺᇹ࿐ളྙӮਅݺ
            ׮ׄ E ᄎ׮ਫ਼ࣥ෮ᄝჵ֥ჵྏ Ođ ࡼ҂эਈ DO ಡׄ D                    ֥ࢳีᆰतđ ՖطϜ໤ᇾ໙ีࢳथ్֥ೆׄđ ๝ൈਅ
            ୉ൈᆌ࿈ሇ 90° ֤֞ DO'đ ৵ࢤ O'Fđ Ⴟ൞ O'F = OE =            ݺ֥ “ ඔ࿐ࢳีଆ྘” ॖၛႵֹིॉҳ࿐ള֥థ၍ି
            2đOF ֥ቋཬᆴ̵ ׄྏए৖ࡨ϶̶ࣥ ֩Ⴟ OO' － O'F =                 ৯．Ֆᆃ۱ၩၬഈࢃđ ໡ૌေ۷ࡆᇗ൪“ඔ࿐ࢳีଆ
            5 2 － 2．                                           ྘” ႋھᄸဢ࢝．ေࣞ฻͇ Ֆ “ ඗ี” ሼཟ “ ඗ଆ྘”．
             槡
                ೂഈਆ২൞֒భᇏॉ൫ีđ หљ൞ᇏॉଆ୅൫ี                             ᆞೂ၂أ޽ေष֤࢐ဇđ ҂൞၂Ӕ၂༓֥൙౦đ
            ᇏ֥ಣׄބ଴ׄđ ఃൌᇉ൞࿈ሇ̵ ಆ̶֩ эߐđ ၛ “ܨ                     “ ඔ࿐ࢳีଆ྘” ֥࢝࿐္๝ဢླေ၂۱ປᆜ֥、 ༢๤

            ׸ჰ৘” ູᆷཟđ ൐ࢳथ໙ี֥නਫ਼э֤ࡥჿ๙ӎ．                          ֥ݖӱ．ᆃླေᄝ৐ౢѩᆊ࿊ԛ “Ⴊྮ֥ ”、“сေ֥”
            4   ࢳުනॉ                                           ֥ “ ඔ࿐ࢳีଆ྘” ֥ࠎԤഈđ ቓݺ “ඔ࿐ࢳีଆ྘”
                “ ᇕܨ֤ܨđ ᇕ׸֤׸ ”đ“ܨ׸ჰ৘”๙෌ၞ׭đ                     ݖӱ߄֥࢝࿐đ ѩᄝൌ࡬֥ࠎԤഈ҂؎Ⴊ߄ݖӱྟ࢝
            ၞႿࢌੀđ Ⴟ൞ູܼԮѬ． ބᇭ؟֥ඔ࿐ࢳีଆ྘၂                          ࿐Ҧ੻đ ಞ “ ࢳีଆ྘” ष޽ѩࢲԛණݔ．
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