Question

San Antonio, Texas, is located about 30º north of the equator. If the radius of the Earth is about 3959 miles, how far to the nearest mile is San Antonio from the equator?

Answer 1

Answer: 2,073

Explanation:


1) Circumference of the Earth:

Circumference = 2π x radius

⇒ Circumference = 2π × 3959 miles = 24,875.13 miles

2) Distance between San Antonio and the Equator.

Note that that distance corresponds to the arc length of a sector of 30°.

That let's you to set the proportion:

$\frac{24875.13}{360} = \frac{x}{30}$

From which you can clear the unknown:

x = 30 × 24,875.13 / 360 = 2,072.93

Which rounded to the neares mile is 2,073