# Chapter 1 - Measurement - Problems: 1a

${2*\pi*radius}$ $={2*3.142*6370}$ $=40029\approx 40000$ km

#### Work Step by Step

Since we know that 1 kilometer = 1000 m, Earth's radius = 6370000 m= 6370 kilometers The formula for the circumference is 2*$\pi$*radius, Therefore, $2*\pi*radius={2*3.142*6370}=40029\approx 40000$ km

After you claim an answer you’ll have 24 hours to send in a draft. An editor will review the submission and either publish your submission or provide feedback.