1. Divide the pressure in psi by 6.4516 to convert it to pounds per square centimeter. For example, you want to convert a pressure of 20 psi: 20 / 6.4516 = 3.10 lb./sq.cm. 2. Multiply
http://www.ehow.com/how_8238224_calculatepsibar....

by using pythagoras therom and using the the cosine rule pounds per square inch is really the result of an elephant.
http://wiki.answers.com/Q/How_do_you_calculate_psi

Linear footage just means measuring footage in a line as opposed to square feet or cubic feet so you would just measure from one point to another using feet.
http://www.ask.com/webanswers/Reference/Other/how...

As long as the amount of air has not changed, and neither did the Temperature, then the pressure inside the structure is inversely proportional to the volume of the structure, or:
http://answers.yahoo.com/question/index?qid=201309...
