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 https://vle.mathswatch.co.uk/images/questions/question17982.png thank u :)

 Mar 24, 2020
 #1
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The distance, D,  from  A  to F  is  given  by  the distance formula  in 3D

 

This  is  given by

 

D = √ [ AB^2 + BC^2  + CF^2  ]

 

D  = √[x^2 + x^2  + x^2]

 

20  =  √ [x^2 + x^2 + x^2]      square  both sides

 

400 = x^2 + x^2 + x^2

 

400   =  3 x^2        divide  both sides  by 3

 

[ 400 / 3 ]  = x^2       take the positive square root of  both sides

 

√[400/3]  = x  = 20/√3   =  20√3 / 3  cm  ≈ 11.547  cm

 

 

cool cool cool

 Mar 24, 2020

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