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Question Number 180897 by depressiveshrek last updated on 18/Nov/22

Commented by depressiveshrek last updated on 18/Nov/22

∣AB∣=3  ∣BC∣=5  BE=EC  ∣CD∣=1  Find the area of the white (not the gray one) area

AB∣=3BC∣=5BE=ECCD∣=1Findtheareaofthewhite(notthegrayone)area

Commented by manxsol last updated on 19/Nov/22

Commented by mr W last updated on 19/Nov/22

fine!  but please post answer as “answer”,  not as “comment”!

fine!butpleasepostanswerasanswer,notascomment!

Commented by manxsol last updated on 19/Nov/22

it is understood Sr.W, excuse me

itisunderstoodSr.W,excuseme

Commented by mr W last updated on 19/Nov/22

thanks alot!

thanksalot!

Answered by mr W last updated on 19/Nov/22

Commented by mr W last updated on 19/Nov/22

AC=(√(5^2 −3^2 ))=4  AE=BE=(5/2)  DG=(1/4)×AE=(5/8)  CG=(1/4)×CE=(1/4)×(5/2)=(5/8)  ((DF)/(DB))=((GE)/(GB))=(((5/2)−(5/8))/(5−(5/8)))=(3/7)  [ΔAEB]=(([ΔABC])/2)=((3×4)/(2×2))=3  [ΔADB]=((3×3)/2)=(9/2)  [ΔADF]=(3/7)×[ADB]=((27)/(14))  white area=((27)/(14))+3=((69)/(14))

AC=5232=4AE=BE=52DG=14×AE=58CG=14×CE=14×52=58DFDB=GEGB=5258558=37[ΔAEB]=[ΔABC]2=3×42×2=3[ΔADB]=3×32=92[ΔADF]=37×[ADB]=2714whitearea=2714+3=6914

Commented by mr W last updated on 19/Nov/22

alternative:  A(0,0)  E((3/2),2)  D(0,3)  eqn. of AE:  y=((4x)/3)  eqn. of BD:  y=3−x  intersection point F:  y=((4x)/3)=3−x  ⇒x=(9/7), y=((12)/7)  [ΔAEB]=((2×3)/2)=3  [ΔADF]=(3/2)×(9/7)=((27)/(14))  white area=3+((27)/(14))=((69)/(14)) ✓

alternative:A(0,0)E(32,2)D(0,3)eqn.ofAE:y=4x3eqn.ofBD:y=3xintersectionpointF:y=4x3=3xx=97,y=127[ΔAEB]=2×32=3[ΔADF]=32×97=2714whitearea=3+2714=6914

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