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# U.S. customary units: distance

CCSS.Math:

## Video transcript

let's talk a little bit about the US customary units for distance if we go to a human scale the most typical used unit in the US customary system would be the foot and as you can imagine the term foot and if you have many of them you are now talking about feet comes from the same word on the human body we have a foot or we have two we have two feet now not everyone's feet are the same length but the length of a foot is roughly a little bit larger than most people's feet and there are definitely peoples who there are definitely people whose feet are the size of a foot and if you're in the US you've probably heard of people measuring their height in terms of feet so for example a a slightly above average a man a slightly above average height would have a height of 6 feet so for example right over here see this this gentleman right over here was slightly above average height his height might be 6 feet and that might also be his wingspan so it would be a distance something like that if you wanted to measure things that are a little bit smaller say smaller than a foot or if you wanted to measure parts of a foot then you would go to the inch then you would go to the inch and the relationship between the foot and the inch is that 12 inches 12 inches are equal to 1 are equal to one foot so for example this little mouse right over here it might be reasonable to measure it in inches on this scale an inch an inch might be might be something like might be well depending on the size the mouse an inch might be something like that it's also useful for measuring things like human height because very few people are a whole number of feet they're usually some fraction of feet so for example for example I am 5 5 feet and 9 inches and 9 inches and sometimes this is denoted as 5 and you have this you have this apostrophe here 1 ' and then foot nine inches and this is two apostrophes kind of saying hey you're going the next unit down this is the these are the inches right over here now if you want to go to things that are larger than maybe human scale you we have units for that as well including the yard the yard is equal to three feet is equal to three feet and three feet well each foot is 12 inches so this is the same thing as 36 36 inches and this is most typically used for measuring measuring distances of a lot of some kind and in in the United States most famously for in football so your regulation size football field the playing field the distance between the end zones is exactly is exactly 100 and you can't see my writing there is exactly 100 100 yards is 100 yards is this distance this distance right over here right between the end zones now if you want to measure even longer distances that's where we go to the mile we go to the mile and all of these units are ancient units going back actually thousands of years and the mile I had based on the reading I found was even used in Roman times and actually that's some of the first that's first some of the first examples of the of this term being used and it was it really comes from the same root word as a thousand of Mille of a thousand footsteps of a Roman soldier and now a standard mile is exactly 5,280 feet 5280 5,280 feet and if you wanted to figure out this in inches you could just multiply by 12 but they just get a sense of a mile here's a mile on this map of New York so there are parts so if you wanted to put it right on a Manhattan this distance right over here this distance right over here is about a mile so you want to measure really far distances either from one point in a city to another or maybe even the distance between cities or maybe even the the size of the planet or even the distance from the earth to the moon or something like that you will hear that referenced in miles even the distance between the Earth and the Sun people say it's a 93 million miles if you're talking about maybe a plot of land you want to measure its dimensions you're talking about a football field and yards feel appropriate if you're kind of getting to human scale well human scale on one level but you could get a little bit larger if you're maybe talking about the height of a building or something like that or you're still talking about measurements of say a plot of land you will still hear people talk in terms of feet and if you're measuring either parts of a foot or things that are smaller than a foot that's when inches come into play