Chapter 12.4, Problem 17WE

To determine

To find: The area covered be water to the nearest million square kilometres.

Answer to Problem 17WE

The area covered by water is $358054603.2{\text{ km}}^2$ .

Explanation of Solution

Given information:

Approximately 70% o the earth’s surface is covered by water and the radius of the earth is 6380 km.

Calculation:

Since, the earth is in the shape of the sphere.

The area sphere is given by

  $A=4\pi r^2$ where $r$ is the radius of the sphere.

Here, radius of the earth is given as

  $r=6380\text{ km}$

Therefore, area of the earth is given by:

  $\begin{array}{l}A=4\pi {\left(6380\right)}^2\\ A=4\times \pi \times 6380\times 6380\\ A=511506576{\text{ km}}^2\end{array}$

Since, 70 % is covered by water. Therefore, area covered by water is

  $\begin{array}{l}A=70\%\text{ of }\left(511506576\right)\\ A=\frac{70}{100}\times 511506576\\ A=358054603.2{\text{ km}}^2\end{array}$

Hence,

The area covered by water is $358054603.2{\text{ km}}^2$ .