How big is the Earth?

The Earth size : is neither the largest nor smallest planet in our solar system. It is the largest of the non-gaseous planets (Mercury, Venus, Mars, and Pluto), but is significantly smaller than the giant gaseous planets (Jupiter, Saturn, Uranus, and Neptune). Below are the specific dimensions of the Earth, which can be used to perform calculations with the assumption that the Earth is a sphere. Though not a perfect sphere, we assume it is a sphere for the sake of mathematical calculations to figure out the Earth's size, volume, surface area, and circumference; all of these all can be calculated knowing only the radius (r) of the Earth and the number pi.

The radius (r) of the Earth is 6,400 kilometers.
The diameter (d) of the Earth is twice the radius.
d = 2r
d = 12,800 kilometers (8,000 miles)
Knowing this, one can easily calculate the circumference and the volume of our planet.
To calculate the circumference (C) of the Earth, use the formula

C = 2 * (3.14) * 6,400 km
C = 6.28 * 6,400 km
C = 40,192 km (24,000 miles)

In other words, if you could walk around the Earth on the Equator, you would have to walk over 40,000 kilometers, or about 24,000 miles, which is 8 times the distance from Los Angeles to New York!