Find the length of the third side. If necessary, write in simplest radical form.

Answer:
third side = 6
Step-by-step explanation:
Using Pythagoras' identity in the right triangle.
The square on the hypotenuse is equal to the sum of the squares on the other 2 sides.
let the third side be x , then
x² + 4² = (2[tex]\sqrt{13}[/tex] )²
x² + 16 = 52 ( subtract 16 from both sides )
x² = 36 ( take square root of both sides )
x = [tex]\sqrt{36}[/tex] = 6