Understanding the Concept
* Earth's Shape: The Earth is an oblate spheroid (slightly flattened at the poles and bulging at the equator).
* Latitude: Lines of latitude are circles that run parallel to the equator.
* Circumference: The distance around a circle is its circumference.
Calculation
1. Radius at 70° North:
* The Earth's equatorial radius is approximately 6,378 km.
* We need to find the radius at 70° North. This is done using the cosine of the latitude:
* Radius at 70° North = Equatorial radius * cos(70°)
* Radius at 70° North ≈ 6,378 km * cos(70°) ≈ 2,180 km
2. Circumference at 70° North:
* Circumference = 2 * π * radius
* Circumference at 70° North ≈ 2 * π * 2,180 km ≈ 13,710 km
Therefore, the distance around the Earth at 70 degrees North latitude is approximately 13,710 kilometers.
