Respuesta :

[tex] \frac{6}{15} [/tex] = [tex] \frac{2}{c} [/tex]   Cross multiply (6 x c and 15 x 2)
6c = 30   Divide both sides by 6
  c = 5
it's a proportion.
6*c=15*2
6c=30
6/6=30/6
c=5