1. The problem statement, all variables and given/known data This isn't a specific problem, but my professor told us that we can calculate the size of a star if we know the temperature of it. 2. Relevant equations Stefan-Boltzmann Law, Wien's displacement law. 3. The attempt at a solution With the temperature i can also get the intensity with Stefan-Boltzmann law and intensity is power over area and area is what i want. But I don't see how I am supposed to be able to calculate area without also knowing the power. My professor also mentioned wavelength which I know I can calculate with Wien's displacement law if i know the temperature, but I can't figure out how that will help me.