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.
To obtain the profit maximizing output quantity, we start by recognizing that profit is equal to total revenue (TR) minus total cost (TC). Given a table of costs and revenues at each quantity, we can either compute equations or plot the data directly on a graph.