Respuesta :

Answer: 4cm

Step-by-step explanation:

Let the unknown side be x , then

from Pythagoras rule :

[tex]x^{2}[/tex] = [tex]5^{2}[/tex] - [tex]3^{2}[/tex]

[tex]x^{2}[/tex] = 25 - 9

[tex]x^{2}[/tex] = 16

x = 4