Is there a shorter way to answer this question?
Radio waves ina vacuum travel a distance equal to seven times the circumference of earth in 1 s. If the radius of Earth is 6 318 138.7m, what is the speed of the radio waves in kilometres per hour?
C = 2πr
Mutliply that value by 7 and convert to Km/hour
6,318,138.7m = 6,318.1387Km
3600 seconds = 1 hour