1. Stating the problem: We are given two points on Earth, \( A(50^{\circ}N, 32^{\circ}W) \) and \( B(50^{\circ}S, 32^{\circ}W) \), and need to find the distance between them. The Earth's radius is given as 6400 km and \( \pi = 3.14 \). 2. Since the points share the same longitude \( 32^{\circ}W \) but are in opposite hemispheres (one 50° north, the other 50° south), the shortest path between them is along the meridian (a great circle passing through poles). 3. The angular distance between the two points in latitude is \( 50^{\circ} + 50^{\circ} = 100^{\circ} \). 4. The arc length \( d \) on the sphere for angle \( \theta \) in degrees is given by: $$ d = \frac{\theta}{360^{\circ}} \times 2\pi r $$ where \( r=6400 \) km and \( \theta=100^{\circ} \). 5. Substitute the values: $$ d = \frac{100}{360} \times 2 \times 3.14 \times 6400 $$ 6. Calculate step-by-step: $$ \frac{100}{360} = \frac{5}{18} \approx 0.2778 $$ $$ 2 \times 3.14 = 6.28 $$ $$ 6.28 \times 6400 = 40,192 $$ $$ d = 0.2778 \times 40,192 \approx 11,164.44 \text{ km} $$ 7. Final answer: The distance between points A and B along the surface of the Earth is approximately \( 11,164.44 \) kilometers.