In Asyptotic notation if g(n) < f(n) is it possible to have f(n)<=c*g(n)
Everything depends on the type of relation you want to define between f and g.

In O and Ω you just have to find one c>0 and one N for which the corresponding inequality between f and g holds and the relation shall be established.

In o and ω you have to show that for every c>0 you can find some N such that the corresponding inequality shall hold for all n > N.

Perhaps this can help you understand it better.