Question

Earth’s surface is approximately 70% water. There is no water on the surface of Mars, and its diameter is roughly

half of Earth’s diameter. Assume both planets are spherical. The radius of Earth is approximately 4,000 miles.
The surface area of a sphere is given by the formula ???? = 4????????^2, where ???????? is the radius of the sphere. Which has
more land mass, Earth or Mars? Use scientific notation in your

Answer 1

Earth

Explanation:

You don't need scientific notation.

The areas of similar figures are proportional to the square of their linear scale factor. If Mars is 1/2 the diameter of Earth, its total surface area is (1/2)² = 1/4 that of Earth.

That is, the land area of Mars is 25% of the total area of Earth.

The land area of Earth is 1-70% = 30% of the total area of Earth. 30% is more than 25%.

Earth has more land area than Mars.