Okay or let's say we knew with the

Okay or let's say we knew with the pressure was a pretty good asset we do it after was the volume we didn't know if the amount of gas once we know how much we had we can figure out that fourth characteristic by rearranging ideal gas law for an canceling out R and T on one side rearranging it to solve for N and deploy again the pressure the following the temperature and could figure out the amount of gas so in other words if we know three in three characteristics we can always figure out what for this so you may be asking yourself okay so are what's our or is what we call a constant.