Chapter 0.7, Problem 16E

To determine

To calculate: the length of the tunnel to the earth’s centre.

Answer to Problem 16E

  $\text{3978}\text{.9 mi}\text{.}$

Explanation of Solution

Perimeter is the total length of the boundary in the figure. The perimeter of the circle is:

  $P_{\text{circle}}=(2\pi r)or(\pi d)$

  $\begin{array}{l}25000=2\pi (r)\\ r=\frac{25000}{2\pi }\\ r=3978.87\approx 3978.9\end{array}$