Chapter 1, Problem 1.3CYU

Check Your Understanding We know horn Figure 1.4 that the diameter of Earth is on the order of ${10}^7\text{ m}$ , so the order of magnitude of its surface area is ${10}^{14}{\text{m}}^{\text{2}}$ . What is that in square kilometers (that is, km2)? (Try doing this both by converting ${10}^7\text{ m}$ to km and then squaring it and then by converting ${10}^{14}{\text{m}}^{\text{2}}$ directly to square kilometers. You should get the same answer both ways.)