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Question Number 187774 by normans last updated on 21/Feb/23

Answered by mr W last updated on 21/Feb/23

Commented by mr W last updated on 21/Feb/23

Method I  a=side length of regular hexagon  let OP=d  sin α=(h_1 /d)  sin β=(h_3 /d)  α+β=(π/3)  cos (α+β)=cos (π/3)=(1/2)  ((√((d^2 −h_1 ^2 )(d^2 −h_3 ^2 )))/d^2 )−((h_1 h_3 )/d^2 )=(1/2)  (d^2 −h_1 ^2 )(d^2 −h_3 ^2 )=((d^2 /2)+h_1 h_3 )^2   ⇒3d^2 =4(h_1 ^2 +h_3 ^2 +h_1 h_3 )  cos (α−(π/6))=((h_2 +(((√3)a)/2))/d)  (√3) cos α+sin α=((2h_2 +(√3)a)/d)  ((√(3(d^2 −h_1 ^2 )))/d)+(h_1 /d)=((2h_2 +(√3)a)/d)  (√(3(d^2 −h_1 ^2 )))+h_1 =2h_2 +(√3)a  (√(4(h_1 ^2 +h_3 ^2 +h_1 h_3 )−3h_1 ^2 ))+h_1 =2h_2 +(√3)a  h_1 +2h_3 +h_1 =2h_2 +(√3)a  ⇒(((√3)a)/2)=h_1 +h_3 −h_2   similarly  ⇒(((√3)a)/2)=h_4 +h_2 −h_3   ⇒h_4 +h_2 −h_3 =h_1 +h_3 −h_2   ⇒h_4 =h_1 +2(h_3 −h_2 )  ⇒h=h_1 +h_4 =2(h_1 +h_3 −h_2 )  ⇒X+A_2 =2(A_1 +A_3 −A_2 )  ⇒X+7=2(10+3−7)=12  ⇒X=5

MethodIa=sidelengthofregularhexagonletOP=dsinα=h1dsinβ=h3dα+β=π3cos(α+β)=cosπ3=12(d2h12)(d2h32)d2h1h3d2=12(d2h12)(d2h32)=(d22+h1h3)23d2=4(h12+h32+h1h3)cos(απ6)=h2+3a2d3cosα+sinα=2h2+3ad3(d2h12)d+h1d=2h2+3ad3(d2h12)+h1=2h2+3a4(h12+h32+h1h3)3h12+h1=2h2+3ah1+2h3+h1=2h2+3a3a2=h1+h3h2similarly3a2=h4+h2h3h4+h2h3=h1+h3h2h4=h1+2(h3h2)h=h1+h4=2(h1+h3h2)X+A2=2(A1+A3A2)X+7=2(10+37)=12X=5

Answered by mr W last updated on 21/Feb/23

Commented by mr W last updated on 21/Feb/23

Method II  say P(k,h_3 )  eqn. line L1:  y=(√3)x  h_1 =(((√3)k−h_3 )/( 2))  ⇒(√3)k=2h_1 +h_3   eqn. line L2:  y=−(√3)(x−a)  h_2 =(((√3)k+h_3 −(√3)a)/2)  2h_2 =(√3)k+h_3 −(√3)a  ⇒(√3)a=2(h_1 +h_3 −h_2 )  eqn. of line L4:  y=(√3)(x−2a)  h_4 =−(((√3)k−h_3 −2a(√3))/2)  h_4 =−((2h_1 +h_3 −h_3 −4(h_1 +h_3 −h_2 ))/2)  h_4 =h_1 +2(h_3 −h_2 )  h=h_1 +h_4 =2(h_1 +h_3 −h_2 )  X+A_2 =2(A_1 +A_3 −A_2 )  X+7=2(10+3−7)=12  X=5

MethodIIsayP(k,h3)eqn.lineL1:y=3xh1=3kh323k=2h1+h3eqn.lineL2:y=3(xa)h2=3k+h33a22h2=3k+h33a3a=2(h1+h3h2)eqn.oflineL4:y=3(x2a)h4=3kh32a32h4=2h1+h3h34(h1+h3h2)2h4=h1+2(h3h2)h=h1+h4=2(h1+h3h2)X+A2=2(A1+A3A2)X+7=2(10+37)=12X=5

Commented by mr W last updated on 21/Feb/23

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