Question 1005671
Let's see...
The circumference of the trail is C = 2(pi)r = 23.236 km.
If the skier skis clockwise 7.5 km, they have traversed .323 of the circle, or 116.2 degrees.
Subtracting 90 degrees, they are 26.2 degrees west of south, ata distance of 3.7 from the origin.
Thus their position would be (-3.7sin(26.2), -3.7cos(26.2)) km.
In radius lengths, that is just (-sin(26.2), -cos(26.2)) of them.
How's that?