Kayla draws the image

There is no formula. The speed of light is a fundamental constant which appears in other formulas but there’s no formula to compute the numerical value.Well, actually, that’s not quite right. The numerical value in meters per second is known exactly, because we use the speed of light to define the meter. It is: c=299,792,458 m/sc=299,792,458 m/s . Exactly. But the thing is — this value is purely an artifact of our unit system. Other unit systems will give other values, so the number value is entirely arbitrary.