Estimate the depth of the hypothetical global ocean in kilometers before any continents or oceanic islands had formed. Assume that the total volume of water on the surface of the Earth was 1.65 × 109 km3
Area of a sphere (A) = 4πr2
Area of the Earth AE = 4 × 3.14 ×(6378)2
AE = 5.109 × 108 km2
Volume of water Vo = 1.65 × 109 km3
VO = d × AE, where d = depth of the ocean in kilometers.
d = Vo/AE = (1.65 x 109)/(5.109 x 108) = 3.23km
