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Find the height of the line with the question mark !

 

 Feb 4, 2021
 #1
avatar+268 
+6

The Answer must be 4, as the top of the line with the question mark is half of the side with length 8.

 

1/2 x 8 =4

 

Hope that helps!!! :)

 

🙃🙃👌

 Feb 4, 2021
 #2
avatar+118470 
+1

Let A  be  the top left  vertex of the  figure

B =the bottom left vertex of the  figure

C = the  bottom right  vertex

D = top right  vertex

E  = the intersection of the diagonals

FE  = the  height we are looking for

 

Note  that triangle ABE  is similar to  triangle  CDE

So   the  altitude of  ABE  to the altitude of   CDE  =12 : 8 

 

Therefore   BF  = (12)/ (12 + 8) BC  =  (12/20) BC

So  FC  =  (8/20) BC

 

And  triangle ABC  is similar to triangle  EFC

 

 

So

 

AB / BC   =  EF /FC

12 / BC  = EF / FC

12/ BC  =  EF /  [( 8/20) BC]

 

12 =  EF / (8/20)

 

12  (8/20)   = EF

 

96/20  = EF   =  24/5  =  4.8    =  ?

 

cool cool cool

 Feb 4, 2021
 #3
avatar+268 
+6

Oh. I get your reasoning but like-

 

The top of the line with a question mark should be half of the line with 8 centimetres which means it's 4?

 

That's what I see-

So could you please explain what I did wrong?

IhaveOBJD  Feb 4, 2021
 #4
avatar
0

NOW what do you see IhaveOBJD ?

 

 You have to be careful with what you see as diagrams are often 'not to scale'  or misrepresented....

 

Guest Feb 4, 2021
 #5
avatar+268 
+6

Ohhhhhh. Thanks 😊 

IhaveOBJD  Feb 5, 2021

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