ccruz58 wrote:

For the first problem which is computing area between 4 cities, do you have to convert the input for the points into radians before using the formulas? Also is the great circle distance formula correct? Is it the right formula since there is no sphere involved. The area is a 2d quadrilateral...

Latitude and Longitude are measured in degrees, so.... review the slides or the Math API to see what units the trigonometric functions require.

Also yes the formula is correct.... the sphere involved is the one we live on.