To measure the distance to the Moon using this method, you first need to find two values: the angular radius of the Moon's disc and the angular radius of the Earth's shadow (where it cuts the Moon). Once you have these, you can use them in the relevant equation, which in this case is either the equation for the distance [i]L [/i](in Earth radii [i]e[/i]) from the Earth's centre to the centre of the Moon's disc, or the distance [i]M [/i](in Earth radii [i]e[/i]) from the Earth's centre to the centre of the Moon's spherical body. On average, the difference between [i]M [/i]and [i]L [/i]is around 3660 metres, which is negligible for most purposes.