Translation:This room is four meters long and five meters wide.
Not just unusual, it's downright impossible. Unless a static, never-changing, orientable sequence of dimensions is provided, the length trait is always given to the largest dimension of the two horizontal possibilities. This is one of the "rules" of the language. The only way this could possibly make sense is if we don't understand something about how Russians measure length.
After remodeling kitchens, laying carpet, and building basements, I must disagree with you. Length is always the longest lateral direction.
reference.com even has this to say about it: "Length vs. Width:
When looking at a two-dimensional object, it might be difficult to decide which side or measurement refers to the length and which side refers to width. If a person is looking at a rectangular shape, the length should refer to the longest side. One can equate length with the word "long" in this instance. Conversely, width would refer to the shorter side and is used to describe how wide the rectangle is."
Are you sure anybody uses it this way? Because if they do it raises endless questions and no less potential confusion.
Consider this, will entering a street from a perpendicular side street, alter the width and length of the street to suit our perspective? Yielding a 70-meter long and 20km wide street?
If not? Where do you start using relative width/length, does a door has to be involved? Then what if we go out of a building's door to a street.
Or maybe relative measurements are only when entering a space not going out of one, then what about entering, through a door, a railroad platform?
In short, while I might, grudgingly, accept the use of relative width/length for a room with one door on one wall because it's deterministic, in any other context I wouldn't know how to use or understand it.
I'm not sure of any philosophical reasoning behind it, but I do know that this construct is following the accusative case (в длину́). The same rule is used when talking about something happening on a certain day or at a specific time:
«Я пробегу́ пя́ть киломе́тров в сре́ду.» // "I will run five kilometers on Wednesday."
«Мы́ с тобо́й встре́тимся в пя́ть часо́в.» // "You and I will meet at five o'clock." (Harder to see here because many words' accusative forms are the same as their nominatives.)
You are asking why certain grammatical cases are used in a given situation. I'm afraid no one will answer you. Just think of it as popular word collocations: в ширину, в длину, в высоту, в глубину.
(Unexpectedly, the accusative is also used with speed and time: 100 метров в секунду, Он уехал в субботу / He left on Saturday, Он был там всю зиму / He was there all winter)
The room is 4 x 5 meters [four by five meters]. Sounds good. As for metre v. meter: I probably see more international English than many users because I live in Asia. Km = kilometer on road signs. Learners of English may find the American spelling simpler than the original French - center, theater, meter etc.
The nominative is метр and it declines like a normal masculine noun with a normal consonant ending. The numbers 2, 3 and 4 require genitive singular (два метра) - 5 and greater require genitive plural (5 метров). Just be careful that each number in Russian is treated individually, for example "twenty-one meters" would still be двадцать один метр, forty-four meters = сорок четыре метра, etc. Six million two hundred and thirty five thousand one hundred and twenty three meters would still be Шесть миллионов двести тридцать пять тысяч сто двадцать три метра.
It depends on where the door is. When you walk into a room, measuring from left to right can be considered "width" while measuring from the door to the opposite wall can be considered "length". If a room is close to being square, then it really doesn't matter.
I think the problem comes from the fact that "long" usually means a far distance, and "long" is associated with "length", so if you have a room which is definitely rectangular in shape, the longer dimension is, well, "long", so it's the "length" - even if it runs left to right when you enter the room. If you enter a very large hall, you can saw it's very long and very wide - so much so that you might not be able to say without measuring it which dimension is the "length" and which is the "width", so you don't know until you actually do the measurement.
Basically, then, all the argument here is based on people having a fixed notion of what a room's dimensions should be, but there are a lot of rooms in the world which don't fit that preconception.
On this point I think they're all the same, actually. Of course the in-house courses have been out for much longer and have many more users (not to mention just being closer to English to begin with, at least compared to Russian) so probably aren't missing too many answers at this point.
Because метра is genitive singular and метров is genitive plural.
Один (1) кот (cat)
Use genitive singular with 2, 3 and 4:
Два, три, четыре кота (2, 3, 4 cats).
Use genitive plural with 5 or higher.
Пять котов (five cats).
For numbers above twenty, always go off the final digit in the number to determine if it should be nominative singular, genitive singular or genitive plural.
For instance, сто один (101) will be nominative singular (сто один кот).
5,434 cats would be genitive singular (пять тысяч четыре ста тридцать четыре кота).
edit: So it doesn't have anything to do with length or width, it's about the numbers used.
Not exactly. One is nominative singular; two, three and four are genitive singular; five through 20 are genitive plural.
There are instances where you'll use the numbers (and nouns) in other cases (I would say dative case is common) in which case the numbers also decline. It gets to be kind of messy which is why many speakers tend to stick to simple sentence structures when it involves numbers so they can stick to the regular nominative/genitive declensions.
OK, thanks - my confusion was why two nouns in an "and" statement are treated differently. I would have assumed any items in a list would be declined the same way because they're all filling the same grammatical role. Am I correct to say that, I wanted to give the width first, it'd still be "... пять метров в ширину и четыре метра в длину"?
When talking about the height of a room, I suppose then you say "в высоту́"
In American English, a room can have horizontal "depth", which would measure the distance from the door to the opposite wall. I suspect, however, that Russian глубина́ does not mean the same thing. Or can it?