You're on a roll —
Step 1: Identify the given coordinates and Earth's radius.
Point P(ϕP=40∘N,λP=45∘W)
Point Q(ϕQ=40∘N,λQ=135∘E)
Radius of Earth (R) = 6370 km (from previous problem context).
π=722 (from previous problem context).
Step 2: Calculate the difference in longitude (Δλ).
Since the longitudes are in different hemispheres (West and East), add them: