a lil help for this q plz...

[D driver]

To measure the distance from 70N 20W to 70N 150E on a polar stereographic, use the latitude scale around approximately:
A.
70°N.
B.
80°N.
C.
85°N.
D.
90°N.

ans-B 80 N

[Goldenrivett]

Since polar stereographic projection distance scale changes with latitude, then simply take the scale at the average latitude of the track drawn.
Because you flew from 20W to 150E (170 degrees of longitude change), then you must have flown very close to the N Pole.

Average latitude was therefore around 80N.

[D driver]

geometrically the highest latitude comes out to be around 87N and the nearest option is thus 85 but answer says 80:*

[Goldenrivett]

geometrically the highest latitude comes out to be around 87N
Correct, but it's not asking for the scale to be used at the highest Latitude - it's asking where is an approximate scale to be used to get an approximate distance. (Average Latitude is better - you went from 70N - 80N - 87N - 80N - 70N. 4 equal sections with average 37/4 degrees above 70 N = 79.25N)

[D driver]

yes i think that's the point...tnx for that :}