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Question Number 189558 by normans last updated on 18/Mar/23

Answered by a.lgnaoui last updated on 19/Mar/23

•(BCEF)est un trapeze    Aire(BCEF)=(((BC+EF)/2))×CE  =(((2,5+y)(x+2))/2)=A_1 +A_2 +9(1)    A_1 =((2,5x)/2)      ⇒(((2,5+y)(x+2))/2)=((2,5)/2)x+9+A_2   ⇒   [y(x+2)=13+2A_2  ]                   2•(ABGF)    Aire=A_4 +A_5 +9  (Aire(HIF)=9)  =(((AB+FG))/2)×AG=(((y+7,5)(x+2))/2)    Aire(ABGF)=((xy+2y+7,5x+15)/2) (2)    A_4 =Aire[(AHCD)−(A_1 +9)]  Aire(AHCD)=(((3+x)(y+5))/2)  ⇒A_4 =Aire(AHBI)=(((3+x)(y+5))/2)−(9+((2,5)/2)x)  =((3y+15+xy+5x)/2)−((18+2,5x)/2)=(((2,5x+3y−3)+xy)/2)          A_4 =((3y+xy+2,5x−3)/2)           A_3 =((5(x−1))/2)  Aire(ABGF)=((2y+7,5x+15+xy)/2)=9+((7,5x+3y+xy−8)/2)  y−5=0    ⇒  y=5  Aire du rectangle=(2+x)(y+5)  =Aire(ABGF)+ire(BCFE) : (1+2)  =((2y+xy+7,5x+15)/2)+((2,5x+5x+5+xy)/2)  =((15x+20+2xy)/2)=((25x+20)/2)    Aire rectangle=12,5x+10    (3)   12,5x+10=10x+20  2,5x=10⇒x=4  donc   (x,y)=(4,5)     ⇒   Aire(rectsngle)=        (2+x)(5+y)=       (4+2)(5+5)=60            −−−−−−   Aire(Rectangle)=60

(BCEF)estuntrapezeAire(BCEF)=(BC+EF2)×CE=(2,5+y)(x+2)2=A1+A2+9(1)A1=2,5x2(2,5+y)(x+2)2=2,52x+9+A2[y(x+2)=13+2A2]2(ABGF)Aire=A4+A5+9(Aire(HIF)=9)=(AB+FG)2×AG=(y+7,5)(x+2)2Aire(ABGF)=xy+2y+7,5x+152(2)A4=Aire[(AHCD)(A1+9)]Aire(AHCD)=(3+x)(y+5)2A4=Aire(AHBI)=(3+x)(y+5)2(9+2,52x)=3y+15+xy+5x218+2,5x2=(2,5x+3y3)+xy2A4=3y+xy+2,5x32A3=5(x1)2Aire(ABGF)=2y+7,5x+15+xy2=9+7,5x+3y+xy82y5=0y=5Airedurectangle=(2+x)(y+5)=Aire(ABGF)+ire(BCFE):(1+2)=2y+xy+7,5x+152+2,5x+5x+5+xy2=15x+20+2xy2=25x+202Airerectangle=12,5x+10(3)12,5x+10=10x+202,5x=10x=4donc(x,y)=(4,5)Aire(rectsngle)=(2+x)(5+y)=(4+2)(5+5)=60Aire(Rectangle)=60

Commented by a.lgnaoui last updated on 19/Mar/23

Answered by mr W last updated on 19/Mar/23

Commented by mr W last updated on 19/Mar/23

0.5×3×(2.5+x)+0.5×5y+A+9=0.5×(5+2.5+x)(3+y)  ⇒2.5y+xy=3+2A   ...(i)  0.5×2.5×(y+1)+9+B+0.5×2x=0.5×(2.5+x)(3+y)  ⇒x+xy=13+2B   ...(ii)  0.5×3×(2.5+x)+A+9+0.5×2.5×(y+1)=0.5×(3+y+1)(5+x)  ⇒x+2.5y+xy=8+2A   ...(iii)  0.5×5y+9+B+0.5×2x=0.5×(2+y)×(5+x)  ⇒xy=8+2B   ...(iv)  (iii)−(i) or (ii)−(iv):  ⇒x=5  from (i):  7.5y=3+2A  ⇒A=((7.5y−3)/2)  from (iv):  5y=8+2B ⇒B=((5y−8)/2)  (A/9)=(9/B) ⇒A×B=9×9=81  ((7.5y−3)/2)×((5y−8)/2)=81  y^2 −2y−8=0  ⇒y=4  reactangle (5+x)(3+y)=10×7=70 ✓

0.5×3×(2.5+x)+0.5×5y+A+9=0.5×(5+2.5+x)(3+y)2.5y+xy=3+2A...(i)0.5×2.5×(y+1)+9+B+0.5×2x=0.5×(2.5+x)(3+y)x+xy=13+2B...(ii)0.5×3×(2.5+x)+A+9+0.5×2.5×(y+1)=0.5×(3+y+1)(5+x)x+2.5y+xy=8+2A...(iii)0.5×5y+9+B+0.5×2x=0.5×(2+y)×(5+x)xy=8+2B...(iv)(iii)(i)or(ii)(iv):x=5from(i):7.5y=3+2AA=7.5y32from(iv):5y=8+2BB=5y82A9=9BA×B=9×9=817.5y32×5y82=81y22y8=0y=4reactangle(5+x)(3+y)=10×7=70

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