ᠴᠢᠪᠠᠭᠠ ᠮᠤᠩᠭᠤᠯ ᠦᠨᠳᠦᠰᠦᠲᠡᠨ ᠤ ᠲᠤᠮᠳᠠᠳᠤ ᠰᠤᠷᠭᠠᠭᠤᠯᠢ — ᠲᠤᠭᠠᠨ ᠪ᠊ ᠤᠬᠠᠭᠠᠨ — ᠨᠠᠢᠮᠠᠨ ᠤᠨ — ᠳᠤᠤᠷᠠᠳᠤ — — ᠦᠷᠴᠠᠶᠢᠬᠤ — ᠲᠡᠭᠰᠢ ᠳᠦᠷᠪᠡᠯᠵᠢᠨ
 ᠨᠠᠢ᠍ᠮᠠᠳᠤᠭᠠᠷ ᠣᠨ ( ᠲᠤᠤᠷᠠᠳᠤ ᠲᠡᠪᠳᠡᠷ ),ᠠᠯᠪᠠᠨ ᠵᠢᠷᠤᠮ ᠤᠨ ᠰᠤᠷᠭᠠᠨ ᠭᠦᠮᠦᠵᠢᠯ ᠦᠨ ᠰᠤᠷᠬᠤ ᠪᠢᠴᠢᠭ᠌,ᠲᠣᠭᠠᠨ ᠤ ᠤᠬᠠᠭᠠᠨ,ᠠᠷᠤ ᠬᠣᠷᠴᠢᠨ ᠬᠣᠰᠢᠭᠤᠨ ᠤ᠋ ᠴᠢᠪᠠᠭᠠ ᠮᠣᠩᠭᠤᠯ ᠦᠨᠳᠦᠰᠦᠲᠡᠨ ᠤ᠋ ᠳᠤᠮᠳᠠᠳᠤ ᠰᠤᠷᠭᠠᠭᠤᠯᠢ ᠦᠷᠴᠠᠢᠬᠤ,ᠲᠡᠭᠰᠢ ᠲᠦᠷᠪᠡᠯᠵᠢᠨ,18.2.3,,,ᠲᠦᠷᠪᠡᠯᠵᠢᠨ ᠲᠡᠭᠰᠢ,,〃,〃,,〃,〃,,,ᠲᠡᠨᠭᠴᠡᠭᠦᠦ ᠲᠠᠯᠠ ᠨᠢ ᠵᠡᠷᠭᠡᠯᠡᠳᠡᠭᠡ,ᠨᠢ 𝟗𝟎° ᠨᠢᠬᠡ ᠦᠨᠴᠦᠭ,ᠲᠡᠭᠰᠢ ᠳᠦᠷᠪᠡᠯᠵᠢᠨ  ᠣ ᠰᠢᠨᠵᠢ ᠴᠢᠨᠠᠷ ᠄,𝐴𝐵=𝐴𝐷=𝐵𝐶=𝐷𝐶,ᠠᠳᠠᠯᠢ ᠬᠠᠵᠠᠭᠤᠳᠤ ᠲᠡᠭᠰᠢ ᠦᠨᠴᠦᠭᠳᠦ ᠭᠤᠷᠪᠠᠯᠵᠢᠨ,ᠲᠠᠯᠠ,ᠦᠨᠴᠦᠭ,ᠳᠠᠰᠢᠭᠤᠪᠴᠢ,𝐴𝐶=𝐵𝐷, 𝐴𝐶⊥𝐵𝐷, AO=BO=CO=DO,∠𝐴𝐵𝐶=∠𝐵𝐶𝐷 =∠𝐶𝐷𝐴=∠𝐷𝐴𝐵= 90 °,2.ᠲᠡᠭᠰᠢ ᠬᠡᠮᠳᠦ ᠴᠢᠨᠠᠷ ᠄,(A),(B),(C),(D),,,,,ᠲᠡᠩᠭᠡᠯᠢᠭ ᠲᠦ ᠲᠡᠭᠰᠢ ᠬᠡᠮᠳᠦ ᠵᠢᠷᠤᠭ ᠲᠦᠷᠰᠦ ᠮᠦᠨ ᠃,ᠲᠦᠷᠪᠡᠨ ᠵᠤᠷᠪᠤᠰ ᠲᠡᠭᠰᠢ ᠬᠡᠮ ᠦᠨ ᠲᠡᠩᠭᠡᠯᠢᠭ᠌ ᠲᠠᠢ ᠃,,,,ᠵᠢᠰᠢᠬᠦᠯᠵᠢᠨ,ᠦᠨᠴᠦᠭᠳᠦ ᠲᠡᠭᠰᠢ,ᠷᠤᠮᠪ,ᠵᠢᠰᠢᠬᠦᠯᠵᠢᠨ ᠶᠠᠮᠠᠷ ᠬᠤᠯᠪᠤᠠᠠᠳᠠᠯ ᠲᠠᠢ ᠪᠤᠢ ︖ ᠲᠡᠭᠰᠢ ᠲᠦᠷᠪᠡᠯᠵᠢᠨ ᠂ ᠷᠤᠮᠪ ᠂ ᠲᠡᠭᠰᠢ ᠦᠨᠴᠦᠭᠳᠦ ᠂,ᠲᠦᠷᠪᠡᠯᠵᠢᠨ ᠲᠡᠭᠰᠢ,ᠷᠤᠮᠪ ᠪᠦᠬᠡᠳ ᠲᠡᠭᠰᠢ ᠦᠨᠴᠦᠭᠳᠦ,,ᠵᠡᠷᠭᠡᠴᠡᠭᠡ ᠨᠢ ᠲᠤᠰ ᠲᠤᠰ ᠡᠰᠡᠷᠭᠦ ᠲᠠᠯᠠ ᠬᠤᠶᠠᠷ ᠬᠤᠤᠰ,,,ᠲᠡᠨᠭᠴᠡᠭᠦᠦ ᠲᠠᠯᠠ ᠨᠢ ᠵᠡᠷᠭᠡᠯᠡᠳᠡᠭᠡ ᠨᠢᠬᠡ ᠬᠤᠤᠰ,,,ᠲᠦᠷᠪᠡᠯᠵᠢᠨ ᠲᠡᠭᠰᠢ,ᠨᠢᠬᠡ ᠦᠨᠴᠦᠭ ᠨᠢ ᠲᠡᠭᠰᠢ ᠦᠨᠴᠦᠭ,,ᠲᠡᠨᠭᠴᠡᠭᠦᠦ ᠲᠠᠯᠠ ᠨᠢ ᠵᠡᠷᠭᠡᠯᠡᠳᠡᠭᠡ,ᠨᠢᠬᠡ ᠦᠨᠴᠦᠭ ᠨᠢ ᠲᠡᠭᠰᠢ ᠦᠨᠴᠦᠭ,ᠲᠡᠭᠰᠢ ᠳᠦᠷᠪᠡᠯᠵᠢᠨ ᠣ ᠮᠠᠭᠠᠳᠯᠠᠯᠲᠠ,ᠬᠤᠪᠢᠶᠠᠨᠠ ᠃ ᠲᠦᠷᠪᠡᠨ ᠪᠦᠷᠢᠨ ᠲᠡᠨᠭᠴᠡᠭᠦᠦ ᠠᠳᠠᠯᠢ ᠬᠠᠵᠠᠭᠤᠳᠤ ᠲᠡᠭᠰᠢ ᠦᠨᠴᠦᠭᠳᠦ ᠭᠤᠷᠪᠠᠯᠵᠢᠨ ᠪᠤᠯᠭᠠᠨ ᠪᠠᠲᠤᠯᠠ ᠄ ᠲᠡᠭᠰᠢ ᠲᠦᠷᠪᠡᠯᠵᠢᠨ ᠦ ᠬᠤᠶᠠᠷ ᠲᠠᠰᠢᠭᠤᠪᠴᠢ ᠨᠢᠡᠨᠡ ᠲᠡᠭᠰᠢ ᠲᠦᠷᠪᠡᠯᠵᠢᠨ ᠢ,ᠵᠢᠱᠢᠶᠡ5:,,A,D,C,B,,,O,ᠨᠢ O ᠳᠦ ᠤᠠᠠᠳᠤᠯᠤᠯᠴᠠᠨᠠ᠂ ABCD ᠂ ᠲᠠᠰᠢᠭᠤᠪᠴᠢ AC,BD ᠦᠭ᠍ᠬᠦᠭ᠍ᠳ᠋ᠡᠭ᠍ᠰᠡᠨ ᠨᠢ ᠄ ᠲᠡᠭᠰᠢ ᠲᠦᠷᠪᠡᠯᠵᠢᠨ,ᠠᠳᠠᠯᠢ ᠬᠠᠵᠠᠭᠤᠳᠤ ᠲᠡᠭᠰᠢ ᠦᠨᠴᠦᠭᠳᠦ ᠭᠤᠷᠪᠠᠯᠵᠢᠨ ∆CDO,∆∆DAO ᠪᠦᠷᠢᠨ ᠲᠡᠨᠭᠴᠡᠭᠦᠦ ᠪᠠᠳᠤᠯᠠᠠᠠᠳᠠᠬᠤ ᠨᠢ ᠄ ∆ABO,∆BCO,,ᠪᠠᠳᠤᠯᠠᠬᠤ ᠨᠢ ᠄,∴𝐴𝐶=𝐵𝐷, 𝐴𝐶⊥𝐵𝐷, AO=BO=CO=DO,∆ABO, ∆BCO, ∆CDO, ∆∆DAO ᠪᠦᠷᠢᠨ ᠲᠡᠨᠭᠴᠡᠭᠦᠦ ᠠᠳᠠᠯᠢ ᠬᠠᠵᠠᠭᠤᠳᠤ ᠲᠡᠭᠰᠢ ᠦᠨᠴᠦᠭᠳᠦ ᠭᠤᠷᠪᠠᠯᠵᠢᠨ,∆ABO≅∆BCO ≅∆CDO≅∆DAO,A,B,D,,,E,,〃,〃,,∟,F,,ᠬᠠᠢᠴᠢᠯᠠᠨᠠ,,E,ᠪᠠᠳᠤᠳᠬᠠᠯ᠄,ᠴᠠᠭᠠᠰᠤ ᠶᠢ ᠡᠰᠭᠡᠭᠡᠳ ᠭᠠᠷᠭᠠᠴᠢᠬᠠᠨᠠ ᠂ ᠶᠠᠭᠠᠬᠢᠭᠠᠳ ︖ ᠦᠵᠡᠭᠦᠯᠦᠭᠰᠡᠨ ᠮᠡᠳᠦ ᠪᠡᠷ ᠨᠤᠭᠤᠯᠪᠠᠯ ᠂ᠲᠡᠭᠰᠢ ᠲᠦᠷᠪᠡᠯᠵᠢᠨ 1. (1) ᠨᠢᠬᠡᠨ ᠤᠷᠳᠤ ᠲᠦᠷᠪᠡᠯᠵᠢᠨ ᠴᠠᠭᠠᠰᠤ ᠶᠢ ᠵᠢᠷᠤᠭ ᠲᠤ,ᠦᠨᠴᠦᠭᠳᠦ ᠲᠡᠭᠰᠢ ᠪᠤᠯᠬᠤ ᠲᠡᠨᠭᠴᠡᠭᠦᠦ ᠲᠠᠯᠠ ᠨᠢ ᠵᠡᠷᠭᠡᠯᠡᠳᠡᠭᠡ,ᠬᠠᠪᠳᠠᠰᠤ ᠶᠢ ᠬᠡᠷᠭᠢᠨ ᠤᠠᠠᠳᠤᠯᠵᠤ ᠤᠯᠬᠤ ᠪᠤᠢ ︖ ᠡᠴᠡ ᠨᠢᠬᠡᠨ ᠬᠠᠮᠤᠭ ᠦᠨ ᠶᠡᠭᠡ ᠲᠡᠭᠰᠢ ᠲᠦᠷᠪᠡᠯᠵᠢᠨ ᠮᠤᠳᠤᠨ (2) ᠨᠢᠬᠡᠨ ᠤᠷᠳᠤ ᠲᠦᠷᠪᠡᠯᠵᠢᠨ ᠮᠤᠳᠤᠨ ᠬᠠᠪᠳᠠᠰᠤ,E,,,D,C,B,∟,,∟,A,ᠪᠤᠢ ︖ ᠦᠨ ᠲᠠᠯᠠᠪᠠᠢ ᠪᠠ ᠲᠠᠰᠢᠭᠤᠪᠴᠢ ᠶᠢᠨ ᠤᠷᠳᠤ ᠨᠢ ᠲᠤᠰ ᠲᠤᠰ ᠭᠡᠳᠦᠢ EB=10m ᠪᠤᠯᠬᠤ ᠶᠢ ᠬᠡᠮᠵᠢᠵᠤ ᠤᠯᠪᠠ ᠃ ᠡᠨᠡ ᠲᠠᠯᠠᠪᠤᠷ ᠲᠠᠯᠠ ᠳᠡᠭᠡᠷᠡ ᠨᠢᠬᠡᠨ ᠴᠡᠭ E ᠶᠢ ᠠᠪᠤᠭᠠᠳ ᠂ EC=30m ᠬᠡᠯᠪᠡᠷᠢ ᠲᠠᠢ ᠲᠠᠯᠠᠪᠤᠷ ᠪᠣᠯᠤᠨᠠ ᠂ ᠰᠡᠷᠭᠦᠯᠡᠩ ᠪᠤᠯᠤᠨ ᠨᠠᠷᠠᠨ AB 2. ᠵᠢᠷᠤᠭ ᠮᠡᠳᠦ ᠂ ABCD ᠨᠢ ᠨᠢᠬᠡᠨ ᠲᠡᠭᠰᠢ ᠲᠦᠷᠪᠡᠯᠵᠢᠨ,ᠲᠡᠭᠰᠢ ᠲᠦᠷᠪᠡᠯᠵᠢᠨ ᠮᠦᠨ ᠦᠦ ︖ ᠶᠠᠭᠠᠬᠢᠭᠠᠳ ︖ 2. ᠲᠤᠤᠷᠠᠭᠢ ᠨᠦᠬᠦᠴᠡᠯ ᠨᠤᠭᠤᠳ ᠢ ᠬᠠᠨᠭᠭᠠᠬᠤ ᠲᠦᠷᠪᠡᠯᠵᠢᠨ ᠨᠢ,ᠲᠡᠨᠭᠴᠡᠭᠦᠦ ᠪᠤᠯᠬᠤ ᠲᠦᠷᠪᠡᠯᠵᠢᠨ ᠃ (4) ᠲᠠᠰᠢᠭᠤᠪᠴᠢ ᠨᠢ ᠬᠠᠷᠢᠯᠴᠠᠨ ᠡᠭᠴᠡ ᠲᠠᠯᠠᠯᠠᠨ ᠬᠤᠪᠢᠶᠠᠬᠤ ᠪᠦᠬᠡᠳ (3) ᠲᠠᠰᠢᠭᠤᠪᠴᠢ ᠨᠢ ᠲᠡᠨᠭᠴᠡᠭᠦᠦ ᠪᠤᠯᠬᠤ ᠷᠤᠮᠪ ᠃ (2) ᠲᠠᠰᠢᠭᠤᠪᠴᠢ ᠨᠢ ᠬᠠᠷᠢᠯᠴᠠᠨ ᠡᠭᠴᠡ ᠪᠤᠯᠬᠤ ᠲᠡᠭᠰᠢ ᠦᠨᠴᠦᠭᠳᠦ ᠃ ᠵᠢᠰᠢᠬᠦᠯᠵᠢᠨ ᠃ (1)ᠲᠠᠰᠢᠭᠤᠪᠴᠢ ᠨᠢ ᠬᠠᠷᠢᠯᠴᠠᠨ ᠡᠭᠴᠡ ᠪᠦᠬᠡᠳ ᠲᠡᠨᠭᠴᠡᠭᠦᠦ ᠪᠤᠯᠬᠤ,ᠦᠷᠭᠡᠳᠭᠡᠯ ᠪᠤᠯᠪᠠᠰᠤᠷᠠᠯ ᠄,ᠬᠠᠮᠤᠭ ᠪᠠᠭᠠ ᠬᠡᠮᠵᠢᠭᠳᠡᠯ ᠢ ᠤᠯ ᠃ P ᠪᠤᠯ AC ᠲᠡᠭᠡᠷᠡᠭᠢ ᠬᠦᠳᠡᠯᠬᠦ ᠴᠡᠭ ᠂ PE+PB ᠶᠢᠨ E ᠪᠤᠯ ᠲᠠᠯᠠ BC ᠲᠡᠭᠡᠷᠡᠭᠢ ᠨᠢᠬᠡ ᠴᠡᠭ ᠂ BE=1, ᠲᠡᠭᠰᠢ ᠲᠦᠷᠪᠡᠯᠵᠢᠨ ABCD ᠶᠢᠨ ᠲᠠᠯᠠ ᠶᠢᠨ ᠤᠷᠳᠤ ᠨᠢ 4,,P,∵𝐴𝐶⊥𝐵𝐷, BO=DO,O,∴𝑃𝐵=𝑃𝐷,PE+PB =PE+PD =DE,ᠳ᠋ᠦ᠋ᠩᠨ᠋ᠡᠯᠳ᠋ᠡ ᠄,1. ᠲᠡᠭᠰᠢ ᠲᠦᠷᠪᠡᠯᠵᠢᠨ ᠦ ᠲᠤᠳᠤᠷᠬᠠᠢᠢᠯᠳᠠ ᠄,ᠭᠡᠨᠡ ᠃ ᠦᠨᠴᠦᠭ ᠨᠢ 90° ᠪᠤᠯᠬᠤ ᠵᠢᠰᠢᠬᠦᠯᠵᠢᠨ ᠢ ᠲᠡᠭᠰᠢ ᠲᠦᠷᠪᠡᠯᠵᠢᠨ ᠨᠢᠬᠡ ᠬᠤᠤᠰ ᠵᠡᠷᠭᠡᠯᠡᠳᠡᠭᠡ ᠲᠠᠯᠠ ᠨᠢ ᠲᠡᠨᠭᠴᠡᠭᠦᠦ ᠪᠦᠬᠡᠳ ᠨᠢᠬᠡ,2.ᠰᠢᠨᠵᠢ ᠴᠢᠨᠠᠷ ᠄,ᠡᠰᠡᠷᠭᠦ ᠲᠠᠯᠠ ᠨᠢ ᠵᠡᠷᠭᠡᠴᠡᠭᠡ ᠂ ᠲᠦᠷᠪᠡᠨ ᠲᠠᠯᠠ ᠨᠢ ᠲᠡᠨᠭᠴᠡᠭᠦᠦ ᠃,ᠡᠰᠡᠷᠭᠦ ᠦᠨᠴᠦᠭ ᠨᠢ ᠲᠡᠭᠰᠢ ᠦᠨᠴᠦᠭ ᠃,ᠬᠤᠪᠢᠶᠠᠬᠤ ᠪᠦᠬᠡᠳ ᠡᠰᠡᠷᠭᠦ ᠦᠨᠴᠦᠭ ᠢᠡᠨ ᠲᠠᠯᠠᠯᠠᠨ ᠬᠤᠪᠢᠶᠠᠨᠠ ᠃ ᠲᠠᠰᠢᠭᠤᠪᠴᠢ ᠨᠢ ᠲᠡᠨᠭᠴᠡᠭᠦᠦ ᠂ ᠬᠠᠷᠢᠯᠴᠠᠨ ᠡᠭᠴᠡ ᠲᠠᠯᠠᠯᠠᠨ,