Please help me in this exercice

[samiboutgoulla]

I attach a photo with the exerice please ignore my writing the rectangle is ABCD , and the point H is defined by the vector AH=16/25 the vector AC
if we use pythagor AC=12,5

 

[khansaheb]

I attach a photo with the exerice please ignore my writing the rectangle is ABCD , and the point H is defined by the vector AH=16/25 the vector AC
if we use pythagor AC=12,5

Please attach your picture so that it can be "read" easily.

Please show us what you have tried and exactly where you are stuck.

Please follow the rules of posting in this forum, as enunciated at:

READ BEFORE POSTING​

Please share your work/thoughts about this problem

 

[The Highlander]

I attach a photo with the exerice please ignore my writing the rectangle is ABCD , and the point H is defined by the vector AH=16/25 the vector AC
if we use Pythagoras AC=12,5

I have 'fixed' your picture but it was such a mess it was easier (clearer) to just re-draw the salient part....

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You began your attempt by using Pythagoras' Theorem and that is all that is required to complete the question too.

Have you not been told about the Converse of Pythagoras' Theorem?
(Follow the link if you don't know about it.)

Once you know the length of AH, that may be used to prove that the angle AHB is 90°

Hope that helps.