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Question Number 206216 by cortano21 last updated on 09/Apr/24

Answered by A5T last updated on 09/Apr/24

HC=(√(108+4))=(√(112))=4(√7)  Let HC meet the circumcircle of the hexagon  at L then, HC×HL=FH×HE=8⇒HL=((2(√7))/7)  sin∠EHC=((√(108))/( (√(112))))=((3(√(21)))/(14))⇒cos∠EHC=((√7)/(14))  ⇒(√(x^2 +2^2 −4x((√7)/(14))))=(√(KD^2 +6^2 −6(√3)×KD))  ⇒x^2 +4−((2x(√7))/7)=KD^2 +36−6(√3)KD...(i)  FK×KD=KC×KL  ⇒((√(108))−KD)KD=(4(√7)−x)(x+((2(√7))/7))  ⇒6(√3)KD−KD^2 =4x(√7)+8−x^2 −((2x(√7))/7)...(ii)  (i)&(ii)⇒32+((2x(√7))/( 7))=4x(√7)+8−((2x(√7))/7)  ⇒x=(√7)≈2.64575

HC=108+4=112=47LetHCmeetthecircumcircleofthehexagonatLthen,HC×HL=FH×HE=8HL=277sinEHC=108112=32114cosEHC=714x2+224x714=KD2+6263×KDx2+42x77=KD2+3663KD...(i)FK×KD=KC×KL(108KD)KD=(47x)(x+277)63KDKD2=4x7+8x22x77...(ii)(i)&(ii)32+2x77=4x7+82x77x=72.64575

Answered by mr W last updated on 09/Apr/24

Commented by mr W last updated on 09/Apr/24

HC=(√(12^2 +8^2 −12×8))=4(√7)  (x/y)×(6/6)×((12)/4)=1  ⇒(x/y)=(1/3) ⇒(x/(x+y))=(1/(1+3))=(1/4)  ⇒x=((HC)/4)=(√7)

HC=122+8212×8=47xy×66×124=1xy=13xx+y=11+3=14x=HC4=7

Answered by cortano21 last updated on 10/Apr/24

Commented by mr W last updated on 10/Apr/24

FK=((FD)/2) is not obvious, must be  proved at first.

FK=FD2isnotobvious,mustbeprovedatfirst.

Commented by A5T last updated on 10/Apr/24

(4/8)×((12)/6)×((DK)/(KF))=1⇒DK=KF⇒FK=((FD)/2)

48×126×DKKF=1DK=KFFK=FD2

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