Question

GEOGRAPHY Earth's circumference is approximately 25,000 miles. If you could dig a tunnel to the center of the Earth, how long would the tunnel be? Round to the nearest tenth mile.

Short answer

The length of the tunnel is 397.7 miles.

Step-by-step solution

Step 1. Given information.

The circumference of Earth’s equator is approximately 2500 miles.

Step 2. Circumference of a circle.

Circumference of a circle with diameter d is given by $C=\pi d$.

A straight line from surface to center of the circle represents the radius of the circle.

Step 3. Calculations.

The given statement that the circumference of Earth’s equator is approximately 2500 miles.

So, the length of tunnel that could be dug from the surface of Earth’s equator to the center will represent the radius of it.

$$\begin{gathered} C=2\pi r \\ 2500=2·\frac{22}{7}·r \\ \frac{2500\times 7}{2\times 22}=r \\ 397.72\approx r \end{gathered}$$

Rounding off to the nearest tenth, we get,

$r=397.7\mathrm{miles}$

Thus, the length of tunnel that could be dug from the surface of Earth’s equator to the center of it is 397.7 miles.