Question

the circumference of the earth is approximately 40 million meters. this is closest to: select the correct answer below: 40 picometers 40 kilometers 40 megameters 40 gigameters

Explanation:

Step1: Convert 40 million meters to scientific - notation

40 million = 40,000,000 = $4\times10^{7}$ meters.

Step2: Convert each option to meters

1. 1 picometer = $10^{- 12}$ meters, so 40 picometers = $40\times10^{-12}=4\times10^{-11}$ meters.
2. 1 kilometer = 1000 meters, so 40 kilometers = $40\times10^{3}=4\times10^{4}$ meters.
3. 1 megameter = $10^{6}$ meters, so 40 megameters = $40\times10^{6}=4\times10^{7}$ meters.
4. 1 gigameter = $10^{9}$ meters, so 40 gigameters = $40\times10^{9}=4\times10^{10}$ meters.

Answer:

40 megameters