True story- I need to delay a 3.5GHz signal by 4uS (microseconds). IF I wanted to use a length of coax to do it, about how long would the line have to be if the velocity constant of the coax is 0.75?

Hint: The numbers work out easy without a calculator!

900m, 2950ft

30m, 98ft

3000m, 9800ft

9m, 30ft

Answer: 900m, 2950ft