Hello, can someone tell me the formula I would need to calculate the size an objects shadow. I’m trying to figure out the size of the moons shadow on the earth during an eclipse. Don’t tell me the answer, just the formula. I would imagine the diameter of the moon and distance from earth is important. Would the distance of the sun from the moon be important? Anyway if someone can nudge me in the right direction i’d appreciate it. Thanks

use perhaps the Riemann’s dzeta function