Answer:
[tex]\sqrt{31}[/tex]
The triangles lengths are: 4, 5, x
Pythagorean theorem: [tex]a^{2}[/tex] + [tex]b^{2}[/tex] = [tex]c^{2}[/tex]
------> [tex]4^{2}[/tex] + [tex]5^{2}[/tex] = [tex]x^{2}[/tex]
----------> 16 + 25 = [tex]x^{2}[/tex]
--------------> 31 = [tex]x^{2}[/tex]
------------------> x = [tex]\sqrt{31}[/tex]
[tex]\sqrt{31}[/tex] is the hypotenuse, so it's the longest side.
