-
ELEC
åºæ¬
äŸé¡
å³ã®å³ã®ããã«,éè§äžè§åœ¢ABC ã®é ç¹ A ãã BCã«äžã
90 åè§åœ¢ãåã«å
æ¥ããããšã®èšŒæ
ããåç·ãAD ãšã, D ãã AB, AC ã«äžãããåç·ãã
ããã DE, DF ãšãããšã, 4ç¹ B, C, F, Eã¯1ã€ã®ååš
äžã«ããããšã蚌æããã
é
000
P.479 åºæ¬äºé
B
481
åè§åœ¢ BCFE ãåã«å
æ¥ããããšããããã°, 4ç¹ B, C, F, Eã1ã€ã®ååšäžã«ã
ãããšã蚌æã§ããã ãŸãè£å©ç· EF ãåŒã
1 察è§ã®åã180°
2è§ã¯ãã®å¯Ÿè§ã®å€è§ã«çãã
ãçšããŠ,åè§åœ¢ BCFE ãåã«å
æ¥ããããšã蚌æãããããçŽæ¥èšŒæããããšããŠ
ãããŸããããªãã
ãã®ãããªãšãã¯,ããããåãèŠã€ããããšããå§ãããšããã
ããããåãèŠã€ãã£ãããååšè§ã®å®ç ã«ãã£ãŠ, åè§åœ¢ BCFE ã®å
è§ãŸãã¯å€
è§ãšçããè§ãèŠã€ããäžã®1ãŸãã¯2ã®ãããã(ããã§ã¯2) ã瀺ãã°ããã
â AED=â AFD=90° ã§ãããã,
åè§åœ¢ AEDF ã¯ç·åAD ãçŽåŸ
A
<æéã
ãšããåã«å
æ¥ããã
â
ã®æ¹é
察è§ã®åã180°ãå©çš
ãã£ãŠ
ããã§
â AFE = â ADE
<匧AEã«å¯Ÿããååš
â ABD=90°-DAB B
D
=90°-â DAE
= ZADE
ããªãã¡
ããã«
â ABD= â AFE
ãããã£ãŠ, åè§åœ¢ BCFE ãåã«å
æ¥ãããã, 4ç¹B,
C, F, Eã¯1ã€ã®ååšäžã«ããã
â EBC = â AFE
çŽè§ãšå
è§£çã®1è¡ç®~3è¡ç®ã§ç€ºããããã«,次ã®ããšããããã
1 çŽåŸã¯çŽè§
çŽè§ã¯çŽåŸ
ãŸã
2 çŽè§2ã€ã§åããªã
ãçŽåŸãªãååšè§ã¯çŽè§ãã«ãªãã éã«ãååšè§ãçŽè§ãªãçŽåŸãã«
ããå©çšãããã®ã§,çŽåŸâçŽè§ãšã
åè§åœ¢ã«