1 gallon = 3.785 liters
That's US gallon, Imperial gallon is 4.54 litres. Our gallon is bigger than yours
And a foot is, of course ~0.30m, 0.9m is 3 feet or a yard.
Standard ceiling here in the UK (new housing) is 2.40m on the ground floor and it is different from builder to builder for the first floor. My 24 year old house was built by some moron who decided to "equalize" - 2.30cm ceiling in both upstairs and downstairs. Pain for furniture - downstairs too low and upstairs too high. Same people put a flat roof on a 24 foot long garage

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A friend of mine was converting miles into kilometers for years and I could never figure out why - it still takes an hour to travel 50 miles at 50mph. Same time as 80km at 80kph
