I've looked over the problem from

http://www.braeunig.us/space/problem.htm#1.5 and I'll like to figure out how to find the chamber pressure of a rocket engine without actually having to test an engine.

I'll be using the SSME to find it's exhaust velocity. The chamber pressure of the engine is 18.9399 MPa or 18,939,900 Pa or 186,922.2798 atm. The only problem is that you cannot find the rest of its schematics in the chart that the site provides. Is there a way to do it because I think if I changed 186,922.2798 atm to 186.9222798 atm by moving the decimal 3 spaces to the left then I can find its Adiabatic Flame Temperature when the chamber pressure is 186.9222798 atm the temperature is 3,650 Kelvin. Because I moved the decimal 3spaces to the left, I move the decimal 3 spaces to the right which gives me 3,650,000 Kelvin. Can I use this method in finding other variables from the P

_{chamber} when its off the charts?