Complete the following item based on the given information.
The volume of a box(V) varies directly with its length(l). Using k for the constant of proportionality, express the relationship between V and l if V varies directly with l.
V = _______
The volume of a box(V) varies directly with its length(l). Using k for the constant of proportionality, express the relationship between V and l if V varies directly with l.
V = _______