Estimate the distance of a fading white dwarf supernova.?

10^8 is 100,000,000 and that is 10,000 times more than 10,000. So the fading white dwarf supernova is 10,000 times brighter than the Cepheid variable star. How far away does something 10,000 times as bright have to be to appear the same brightness? Hint, it is an inverse square law. So the square root of the brightness difference is how many times farther away than the given distance.