Question

What is the approximate distance between Portland, Oregon

Answer 1

5669.71 km

Working
The two cities are located on the same longitude. 
The formula for the distance then is;
Distance = $\frac{∅}{360}$*2*π*3960
where ∅ is the latitude difference-add the latitudes as they are on different sides.
Distance = $\frac{82}{360}$*2*$\frac{22}{7}$*3960
                =5669.71 km