Respuesta :

Answer:

it's 5

Step-by-step explanation:

you should use pythagoras theorem

Answer:

b = 5

Step-by-step explanation:

a^2 + 12^2 = 13^2

a^2 + 144 = 169

         -144    -144

[tex]\sqrt{a^2}[/tex]  = [tex]\sqrt{25}[/tex]

a = 5

[tex]a^2 + b^2 = c^2[/tex] pythagoream theory