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( ) *+,(-#./011(23 4       5  678179:.;<!=/01 (678179      >/?(@AB'C/ /011)C/    5     D  C/E@AFB(G#3 /0111)C/ H          I#$/0111)C/ (G#3   5   D   %  DJK D DJK D LJK M KJK N.O PEQ/;) R21(234NSH/)JTSK/)P*+,(234N:.T7.R 1      /   #   5P2U:VTWOONJ1/XR 1P AB AC DE DC =  AB DE BC DC = / AB DE BE CE = # AB AD DE BE =  DP2U:V5PN7.1B'C//01  A U 1 AB BI AC BC =  AB AC BC CI = / AB BI AC IC = # AB CI AI AC = LP2U:VDPN11)C/Y:.YZ(G#3:[1!J+!\E1R 1SZ OOZ / MNP RQP∆ = ∆ #=1JJ/(]!(^ _P2U:VLWJ`7.E!( )/01NJP(X a  5 L    N  1 ABC AEF∆ ∆ b2*+,cS    AEF ABC ∆ ∆ b2*+,cS5 / AEF ABC∆ ∆ b2*+,cS    # AFE ABC ∆ ∆ b2*+,cS5  5DL HP11)C/N:.dNdd(G#31!!R 1     A B B C AB BC ′ ′ ′ ′ ′ =         B C BC ′ ′ ′ ′ ′ = /           ′ ′ ′ ′ ′ = MPC//'!+1!(^1\+1 P11)C/(G#3Ue1!P 5P11)C/:!/'7!(G#3:[1!P DP11)C/e1!U(G#3:[1!P LP*+,/!:/0111)C/(G#3e*+,(G#3/011 1)C/(XP   NPf&!MJ_(g   !!"#$ 5DJ_(P 21)C/N:!3J(@A/12P hiYJZ7j7@F7.E!( )/01NJ k)R 1 %& % J_( hiYJZ7j7@F7.E!( )/01NJP k)R %'&   %&( J_( D21)C/N/XNS/)JSK/)PEl/3N7?\( )+12/2 SH/)J:V(@A4<!1:.+2+2:[/QN3J:V(@A4 <!1:.+2+2:[N/Q3YP>/!:kC/YP5J_(  mYm !EQ/;))5J_( *+      , /.  0 1  1  B C A E D I B C A F E B C A 6 3 2 x P M N Q R a  5 L    N  *+) NOf7!R  "#$) 2 !! AN AM NC MB ⇒ =  "3455678$   9:7811*+0 9:7811*+  B A C Q H P  0 !#  )HBA ABC∆ ∆  :;<1     =      AHB BAC B chung HBA AB C = = ⇒ ∆ ∆  !# BPH AQH∆ ∆  !#;<1)         BPH cân tai P AQH cân tai Q HAQ PBH BPH AQH ∆ ∆ = ⇒ ∆ ∆  *+ *+ *+ *+ > - - -  "6 ') 9:7811*+0  A B C M N P  9 !#;<1 '?55 9 >+@A0 'B  9 "6;<1 1# 9 "3455678 '=1# 9999999999999999999999999999999999999999999999999999999999 .      AHB BAC B chung HBA AB C = = ⇒ ∆ ∆  !# BPH AQH∆ ∆  !#;<1)         BPH cân tai P AQH cân tai Q HAQ PBH BPH AQH ∆ ∆ = ⇒ ∆ ∆  *+. ′ ′ = MPC//'!+1!(^1+1 P11)C/(G #3 Ue1!P 5P11)C/:!/'7!(G #3 :[1!P DP11)C/e1!U(G #3 :[1!P LP*+,/!:/0111)C/(G #3 e*+,(G #3 /011 1)C/(XP   NPf&!MJ_(g  . 9:7 8 11*+0 9:7 8 11*+  B A C Q H P  0 !#  )HBA ABC∆ ∆  :;<1     =