Multiple choice What is the exact difference between average equatorial and polar radius of the earth? 42.2 km 21.4 km 42.78 km 23.76 km Reveal answer Fill a bubble to check yourself B Correct answer Explanation The Earth is an oblate spheroid. The equatorial radius is approximately 6378.1 km and the polar radius is approximately 6356.8 km, yielding a difference of roughly 21.4 km.