Respuesta :

15.7 cm

Is it a right triangle?

If so we can use Pythagorean Therom:

a^2+b^2=c^2

Solve for c by plugging in a and b

You get c≈6.529931

Perimeter is the sun of all of the sides so just add em together:

6.5+5+4.2= 15.7 cm