I am pretty sure that I have got the others but I can't understand #4b: estimate the distance corresponding to 1 degree of longitude at latitudes of 30 and 60 degrees.

Here are the choices:
1) for 30 and 60 lat, the long distance equal to 1 degree is long. at equator x cosine (lat)
2) for 30 and 60 lat, the long distance equal to 1 degree is long. at equator x sin (lat)
3)for 30 and 60 lat, the long distance equal to 1deg is same as long dist on equator

• um...just under 18 km? - carefuluniverse - October 1, 2005 - 03:23 UTC