Question

In problem R=√R²×+R²y=√(3.0km)²+(1.0km)²

R=2.24km, in what direction she from the starting point?

Answer 1

If

$$R=\sqrt{R^2_x+R^2_y}=\sqrt{(3.0\text{ km})²+(1.0\text{ km})²},$$

then

$$R=\sqrt{10}=3.16\text{ km}.$$

This vector (R) makes the following angle with the 3km-vector:

$$\theta=\text{atan}\frac{1}{3}=18.4°.$$