how to use the results of a method in another method in a different class initialization at vb.net

Question

I have a class which has the following methods:

Public Function rumusbuffer () As Decimal
    buffer = (ukuranblok - pntrblok) / (ukrnrecord + pntrblok)
    Return buffer
End Function

Public Function rumusW () As Decimal
    interblock = pntrblok + ((pntrblok + intrblok) / buffer)
    Return interblock
End Function

how can I make the buffer can be used on its function rumusw but different forms so that her class should be re-initialization .. but the calculation method can rumusbuffer rumusw d use in the method?