German for X rays where 'X'  means   'unknown'. In Europe X-rays are known as Roentgen rays.    X-Radiation is a form of electromagnetic radiation having a  wavelength of   0.01 to 10 nanometers.NS2: The name x-ray was applied to radiation in the same frequency as gamma radiation but which originate from a man-made source.
wikiHow to Calculate Gross Profit Margin. Gross profit is a fairly simple comparison of the cost of the goods your company sells to the income derived from those goods. Gross profit margin is the ratio of gross profit to total revenue expressed as a percentage.
incremental profit analysis. Comparison of estimated incremental (marginal) revenue with the estimated incremental cost of a proposed investment or action, to determine the incremental profit estimated to be generated.