My girlfriend has this question on here college universe course homework and she kind of skipped that day so she is lost. And I don’t know jack crap about this stuff. Anyone have a clue?

If the sun was at an angle of 7.2 degrees from the vertical at alexandria at the same moment it was exactly vertical at syene, what is the circumfrence of the earth? What would the diameter be if the distance measured was 10,000 stades?