math
posted by Rose .
If the distance between location A to B is straight east 10 km. then from B to C is Nw 18KM How far would you be from point C to A.
Would you not need to more information then this to calculate this answer?

Use the Pythagorean Theorem.
(AB)^2 + (AC) ^2 = (BC)^2
substitute for AB and BC.
then solve for AC 
no, just use the cosine law
AC^2 = 10^2 + 18^2  2(10)(18)cos45°  assuming that Nw meant "northwest"
= 169.44...
AC = √169.44.. = appr 13.02 km 
Rose,
Sorry, I got in a hurry.