What would you use to measure a finger in kilometers or something?

Answer 1

You could use any unit of length you like to measure the length of anything. Some units deliver huge numbers, and others deliver microscopic numbers. The trick is to pick the unit that gives you the most convenient number ... a number that's easy to remember, carry around, and write. Here's the example that's relevant to your question: I have approximately 10 fingers. A moment ago, I selected one of them at random, in order to proceed with the investigation of your question. I then measured the selected finger. I shall now give you the measurement in several different units of length/distance. You suggested the kilometer. From the list, see whether you think that's a convenient unit to use for a finger, or whether some other unit produces a more practical number. The length of my randomly-selected finger is: 78,740,000 nanometer 78.74 millimeter 7.874 centimeter 3.1 inch 0.25833 foot 0.07874 meter 0.086111 yard 0.0003914 furlong 0.00007874 kilometer 0.00004893 mile 0.0000000000000000083327 light-year