平行复件性质.ppt

* * Ngergd [ffed LffXh reBgifo Qfnfpcx CfitSeed ]fzj gd Af[fb AfBtdZgpgzg,fbLepgeS ZgeBtpced CC[erpced 19.1 gh? Afpx AfpxLx?CfBwXfwSLpffh wBXeutfedM ⑵Zg+CCBgqZgeB[h zhZffyXfrhAgefXgeSNx ZfBdNxZgeBtpcedUgedgh? ⑴VfifbCCBgqZgeB[hexLeBepzgrpgy[fdLx? Agewx ; AndAgeVf+ : AedmgBtpcedh tfeBx ex Nx QgjCB,fffh Zf,fBe,gpgd ABRrpch ﹒Zggbs Zfos ZfwbsZfosAedmgBtpcedx XfeS x Agpch wch Zfizypfxs ﹒ ZfBfq.Nx ZgbsAedNewSZfosAedZgizdXfeSx ZfjffgXfff[fdmgBtpcedx QffeXepfdM ZfRd Zgizf,gb Nx Ng,gpgff[fd h ZfBfq.Newd ]f,fBzfpq.: Newd Qf,gzf[j Xf,f[j ex 180° O O ∠1=∠2 , ∠3=∠4, ∠A=∠B; AB=CD , AD=BC; ∵ ∠1=∠2 ∴AD//BC ∵ ∠3=∠4 ∴ AB//CD 3 1 B A C D 2 O 4 CfBwXfr ZgeBtpced x CC[erpced wdM; QgVfb Qgg+A[fBr ZfosNx Zg+ Zg+ x QgpLff[fd wBXeuxZf[e,gjXx wdM ; CfBwpzfwSL[h QgVfbAgBgxAedXfeS CC[erpcedx︽ ︾tbAepfBwfepfzfeS﹒ CC[erpced Zf[e,gjXx CC[erpced ex︽ ︾wcjZfizfypfdM; ABCD ABCD 3 B A C D 2 O AB CD AD BC A B C D ABCD AB CD AD BC ① ABCD ② AepfBwfepfr ZfizfeSAefb CCBgifq tS AHOE ABCD BHGC AHGD CDEF ABFE CFOG DEOG BHOF D A B C O H E F G tfeffh Lx? wzgdCC[erpced ZggBfwE CCBgq Zh ZgeBtpced CC[erpced CfBwXfr Zg+ Zg+ A[fBr Zfos QgVfbQgg+ [getyXepfr Zf,fifffpfff[fdZfx Newzfpzfx gh ? tfeffhLx? wicech Agecd ﹒ Xenh AgefXgeSgdQg,gBgfzh VfifbQgpLffzfo AXdmfzfdM﹒Zfrdh Zfos﹒ ZfosNxZg+ Zg+ CfBwXfwSLpffh︾ eefdAfceffpd﹒ ︽QgVfbQgg+A[fBr CC[erpced CCBg,fgd﹒AndZgeBtpced ZgzgBfffepfpzdexAgefzg[gpfdNewd CC[erpcedh [efcx Xenfb: CC[erpcedh A[fBr ZfosNx ZffyXfrh ; CC[erpcedhA[fBr AgefXgeSNxZffyXfrh; B C A D 2 3 4 1 A B C D AD∥ BC AB∥ DC AD=BC AB=DC ∠ A=∠ C ∠ B=∠ D AepfBwfepfr ZfizfeSAefb eeBgifq tS ABCD A B C D 1 2 3 4 AB CD AD BC ∠1= ∠2 ∠3= ∠4 ∠BAD= ∠BCD ∠1= ∠2 AC=CA ∠3= ∠4 AD=BC ∠B= ∠D AB=DC ABCD AC ABCD Ufzh CCBgq zh QgpLdM; ex ?ABC ?CDA ≌