if you have a combo box with 3 columns and only the 1st column is visible to the user, how do you reference the other two columns?

for example, if the combo box is filled as follows:
row1: "1"(visible), "192", ".667"
row2: "2"(visible), "120", ".882"

and i want to use the value in the third column in a mathematical function based on what the user selects in the visible column:

variable = 10 * thirdcolumnvalue

what should i replace thirdcolumnvalue with to get the proper result?

thanks
JD