Implied odds with one to come

[Nougat]

If I wanted to make a calculation of the necessary amount of money to extract from my opponent by evaluating my implied odds against my current call, would the following very rough process work?:

Given that Hero has an inside straight draw and it is of a given four cards such that the villain's hand does not include the necessary rank to make the straight, a call of 50 into a pot of 150 requires a minimum expectation of 438 additional value from the villain if you hit your hand. By crossmultiplying (50/x)=(4/47) where x is defined as the value in the pot, I get x=587.5 and then subtract the size of the current pot (150) to determine the additional amount I need to get in the pot in order to call the initial 50.

Is that the proper way to calculate such things? Assume arguendo that I am drawing to the nuts and thus cannot be bested if I make my hand (odds to win=odds to make my draw).