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## Homework Statement

10.0km [N] + 5.0km [E15S]

## Homework Equations

Cosine Law

## The Attempt at a Solution

If you draw it out you see that 10km is 90 degrees north. From the 10km end, you do E15S for 5km.

Therefore, a = 10km, b = 5km, c = ?, C = 90 - 15 = 75.

Therefore:

c^2 = 10^2 + 5^2 - 2(10)(5) Cos 75

c^2 = 99.12

c = 9.9

Sin Law to find the angle of the resultant

Sin A = Sin B

----- ------

a = b

Sin 75 Sin B

------- = -------

9.9 5

B = 29

So final answer is 9.9km [N29E]

Somehow the answer is 4.2[N35E]...