# How do you find a circumference if given altitude of sun and equinox?

##### 1 Answer

Feb 25, 2016

The formula is 2

#### Explanation:

At equinox instant, Sun S is overhead at equinox Q of the Earth's equator.

At the same instant, it is noon at Q's longitude, at all latitudes. L is one with latitude

The Sun's altitude from L, at noon, is

Using that sides are proportional to opposite angles in the

EL = ES ( cos

I thank the questioner for making me think on this handy formula. .