You need to remember the formula that gives the volume of solid of revolution such that:

Notice in this formula the presence of the equation of the curve that needs to be rotated, hence, the problem needs to provide the equation of f(x).

You need to remember the formula that gives the volume of solid of revolution such that:

Notice in this formula the presence of the equation of the curve that needs to be rotated, hence, the problem needs to provide the equation of f(x).