Chapter 1 - Units, Physical Quantities, and Vectors - Problems - Exercises - Page 28: 1.25

Magnitude: 7.83 km Angle: 37.7 degrees

$\Delta x = 4.0 + cos(45)*3.1$ $\Delta y = 2.6+sin(45)*3.1$ $\text{ Magnitude} = \sqrt{(\Delta y)^2+(\Delta x)^2}=\sqrt{(4.0+3.1*cos(45))^2+(2.6+3.1*sin(45))^2}=7.83\ km$ $\text{ Angle} = arctan(\frac{\Delta y}{\Delta x})=37.7\text{ degrees}$