Question 579254
{{{ x^2 = 26^2 - 18^2 }}}
{{{ x^2 = 676 - 324 }}}
{{{ x^2 = 352 }}}
{{{ x = sqrt( 352 ) }}}
{{{ x = 18.76 }}}
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I suspect there is a misstatement of the 
problem. I think that there is a vertical
height given, but it is not one of the 
sides of the triangle. 
So, the side that is not horizontal can swing
from the vertical height so it is a long
distance or a short distance from
where the hypotenuse meets the horizontal.
The short distance makes the triangle acute.
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I can't see how you get there, though.