Answer:
The length is APPROXIMATELY equal to 12.4.
Step-by-step explanation:
Use the converse of the Pythagorean Theorem ([tex]a^{2}[/tex]+[tex]b^{2}[/tex]=[tex]c^{2}[/tex] [where "c" is both the longest side and the hypotenuse]) since a rectangle's diagonals will always cut it into two right triangles:
[tex]13^{2} = 169[/tex]
[tex]4^{2} =16[/tex]
169-16=153.
[tex]\sqrt{153}[/tex] ≈ 12
or
[tex]\sqrt{153}=12.36931688[/tex]
or if the problem has to be exact (using radicals)
3*[tex]\sqrt{17}[/tex]
I hope this helps ;)
