Saint Petersburg, Russia and Anchorage, Alaska, both have approximately the same latitude of 60 degrees. That means you can reach Saint Petersburg from Anchorage by flying directly east, or directly west. Assume the earth is a sphere of radius 6371 km. (a) By heading directly east, what is the distance from Anchorage (longitude 150 degrees W) to Saint Petersburg (longitude 30 degrees E)?

Distance from Anchorage (longitude 150 degrees W) to Saint Petersburg (longitude 30 degrees E) = 10,002.47 KM

Step-by-step explanation:

As earth is a sphere of radius 6371 km.

Therefore at 60 degree latitude, the radius of circle can be calculated as shown below:

= 6371 * Cos 60

= 3185.5 KM

Saint Petersburg is nearly 180 degree about Anchorage by flying directly east.

So Distance from Anchorage (longitude 150 degrees W) to Saint Petersburg (longitude 30 degrees E) can be calculated as shown below:

= (180 * 2 * 3.1416 * 3185.5) / 360

= 10,002.47 KM

I believe the answer would be 443. I came up with my own way of solving it without going through the long process. Since the pattern is 14 gets added onto each number, I decided to multiply 14 x 47 = 658. Then I added 658 + (-215) and got 443. This is NOT how it should be done, but I if I am wrong, let me know and I'll redo the calculation(s).