The curved part of this figure is a semicircle. What is the best approximation for the area of this figure?

A. 21 + 14.5π units^2
B. 10.5 + 14.5 units^2
C. 21 + 7.25π units^2
D. 10.5 + 7.25π units^2

Planet earth has a mass of 5.9726x10²⁴ kg.then: 5.9726x10²⁴ kg=100% of the total earth mass.if the water´s mass=5x10-4 % of the total mass, we can solve this problem by the rule of three.5.9726x10²⁴ %*10⁻⁴ %x=(5.9726x10²³ kg)(5*10⁻⁴  %) / 100 %=2.9863x10¹⁹ kganswer:   the mass of the planet´s water would be   2.9863 x 10¹⁹ kg.