what is 2.5 Dimension?
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I'm guessing that you're asking what does it mean to say something is 2.5 dimensional, as opposed to 2 dimensional or 3 dimensional.  \n\nAnytime you have a fractional dimension like that, you're dealing with a fractal.  That's where the word "fractal" comes from.  The dimension for an object that is self-similar at many size scales in a complex way can be thought of as an extension of the obvious fact that a uniform object of unit length d in two dimensions has an area of d^2.  In three dimensions, a uniform object of unit  d (a cube with sides d units long) has a volume of d^3, and so on.  \n\nSo, you can generalize this concept and say that something has the dimensionality of whatever power the scale along one axis has to be raised to in order to give the area/volume/whatever.   Since a fractal object has repetition at all scales of some sort of complex pattern, the relationship between scale and total size, the dimensionality, is a non-integer.\n\nSo, for example, if you had a volume which had been "Swiss cheesed" by some sort of algorithmic removal of sub-volumes, and sub-volumes of the remaining volumes, and so on, and so on, to make a fractal sponge, it would have a dimensionality between 2 and 3.
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Mathematically n dimensions can be described but our experience is only 3 dimensions So the properties of fourth dimensonal shapes can be mathematically described and a fourth dimensional quantity that is in units^4 can also be calculated\n\nThis is an argument that the 4th dimension is time. That cannot be the case when one considers the properties in 3d are L, L, and L One would immediately envisage that the 4th, 5th .... nth dimensions would also all be L\n\nA tesseract, the 4 dimensional equivalent to the 2 dimensional square and 3 dimensional cube, is not a time related object at all. Its 3D projection can be build and the objects equivalent of a 2D shadow seen easily. In 4-space it occupies L^4 units^4. Wikepedia has some interesting information and projections of a tesseract
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at the present time we define the universe by four dimensions, length, width, height, and time.\n\nhttp://en.wikipedia.org/wiki/Spacetime
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Currently man believes or percieves only 3 spacial dimensions.  Height, length and depth.  String Theory, the unification theory of quantum and relative gravity hypothesizes up to 11 other spacial dimensions.  God resides where man can not comprehend and angels fear to tread.  Remember, the heart has its reasons of which reason knows nothing.
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Physics believes that there are 12 dimensions. The Bible seems to back that up.\n\nWe know four dimensions: height, width, length and time.
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Basically, the space that you and I experiences daily is 3 dimensions: up/down, left/right, forward/backwards. But space doesn't have to be 3 dimensions. It can be any number of dimensions. Of course, it is very difficult for us 3-dimensional beings to imagine what these dimensions are, or where they are. The problems is that we can NEVER see the fourth spatial dimension, never mind the 5th or the 6th, etc. etc. Let me explain why.\n\nImagine for a moment that we are 2-d beings, not 3-d. And we live on the surface of a sphere (like a ballon). This sphere is our universe. Everything we see, touch and experience happens on the surface of this sphere. We can go left/right and forward/backwards. But we can never go up or down. When we travel in one direction, we will eventually circumnavigate the sphere and make a complete circle, which brings us back to the initial starting point. If we ask the 2-d beings to imagine 3-dimensional space, all we can tell them is that the 3rd dimension (up/down) is orthogonal (a fancy way of saying perpendicular) to the surface of the sphere.\n\nThis is exactly our situation when we talk about the 4th, 5th, 6th, whatever nth dimension. They are defined as the dimension that is orthogonal to the n-1 th space. So the 4th dimension is orthogonal to our 3-dimensional space, and the 5th dimension is orthogonal to the 4-dimensional space, etc. etc.\n\nNow about Super String Theory and these higher dimensions: what the theory predicts is that our universe does indeed have more than 3 spatial dimensions. Some version sof the theory say there are 10, some say there are 11. Whatever the number (it doesn't really matter in our discussion here), these higher spatial dimensions are currently curled up into very very tiny spaces. So what does that mean?\n\nWe now go back to our 2-d being living on a sphere example. For the time being, let's say we are now on a flat 2-dimensional surface (like a sheet of paper). Super String Theory says that the higher dimensions are curled up. So let's consider in our case the 3rd dimension as the curled up dimension. This means that if we were to magnify any point on the 2-d surface all the way to about 10^-35 meters (Planck Length), we will see that there is a tiny loop (like a loose thread on a knitted sweater).\n\nNow imagine if our 2-d being were (1) small enough to see and fit inside the loop, and (2) able now to travel in the 3rd dimension, then for it to go in the up/down direction, the 2-d being will now be just going around in circles inside the loop. Remember in the previous case, our 2-d being can travel in one direction on the surface of the sphere and then return to the same point. Well, here our 2-d being is traversing through the 3rd dimension, except that there is no up and down because the 3rd dimension is "curled up" into a loop. So the 2-d being just goes around the loop in circles.\n\nIf you understood the above, then now we can answer the question, what and where are these higher dimensions in our universe. They are culred up in every point in our 3-dimensional space, and if we were small enough and we could move into these higher dimensions, then we would be moving through these very convoluted curled up loops, but not really able to go anywhere.\n\nBecause these higher dimensions are curled up into such tiny tiny loops (remember 10^-35 meters), only the most elementary structures like "strings" are affected by them. The size of these strings are of course on the order of 10^-35 meters long, and can traverse through the curl up dimensions. When the strings vibrate, the vibrations in the 3 large dimensions don't have any effect, but in the curled up higher dimensions, the vibrations can create resonance like playing a musical note.\n\nThese resonances are the stuff of reality, meaning these vibrational resonances of the strings inside the curled up dimensions is what creates matter and energy and thus everything that&#
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to calculate the area of a 2-dimensional space you always multiply length x width, or in this case height\n\nC
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None.  That is the point.  If they exist is not proved, and hypothetical tests to see if they exist are flawed.  \n\nOn your other question of visualizing multiple dimensions, I have a few hints.  Have you read Flatland yet?  Start there, its good, and not overly mathematical.  Multiple dimensions can mean different things to different scientists.  We use them all the time for their mathematical properties.  But mathematics is just a description, the real world is something observable.  In terms of observation, you would not be able to detect a separate dimension by any means pedantic.  We may be able to prove that physical space has more than three dimensions, but that does not mean that those other dimensions are physical space.  Just like time.  Some particle interactions appear to go backward in time briefly.  What if there is more than one time dimension?  \n\nSo the classic three dimensional physical picture of multiple dimensions will always be flawed by the observers expectation of the properties of the unseen dimension.  Which is why we describe those dimensions using 'imaginary' constructions.  Hope this helps a bit.
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The universe that we live in has only three spatial dimensions. We are limited to length, width, and height, and we can only travel along three perpendicular paths. This page attempts to explain the properties of a hypothetical universe with a spatial fourth dimension. While people generally call time the 4th dimension in the universe we live in, time will be the 5th dimension in my hypothetical universe. \n\nMany fascinating possibilities exist when a spatial fourth dimension is present. Several types of wheels are possible, very complex machines can be built, and many more shapes are possible. Objects can pass by each other more easily, but they are harder to break into multiple pieces. Energy reduces much faster with distance than in the 3rd dimension, so both light and sound are weaker. Much more things can be compacted into a small space, but its much easier to get lost. In this page, I will explore these and many other interesting properties of the fourth dimension.
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Time And Relative Dimension (or Dimensions) In Space
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2.5 times 2.2 = 5.5 lbs
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Actually, the first two answers are right; but, disregarding time, if we were 4-dimensional beings we would still only cast 2-dimensional shadows.\n\nEven 2-dimensional objects also only cast 2-dimensional shadows.  Anyway, what would your 4th dimension be?\n\nShadows are merely the result of an object being between the shadow and the light source; shadow is merely absence of light.  Shadows are always 2-dimensional.\n\nAnd as far as considering time to be a dimension goes, we are IN the dimension of time, but we are not IN the dimensions of width-height-length.  They are attributes used to describe us; they are part of us, we are not part of them.
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If your legs lived in, say, the 4th Dimension - how would your brain be aware of them since it exists only in 3 Dimensions? We are physically in 3 dimensions (time is an illusion made to mark the difference between one state and another) - we can comprehend of separate parts of our bodies being in different dimensions as much as a stick man drawn on a piece of paper can imagine moving freely around the room in 3 dimensions.  We can only visualise higher dimensions using tricks such as looking at the shadows cast when a 4 dimensional object is illuminated inside a computer program.  What would it matter how big the sock was to be pan dimensional? Good question though.
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space might have more than three dimensions; we don't know.  edwin abbott wrote a very famous book called "flatland" about people who were confined to life in a two-dimemsional world, and what it was like to live there.  it was part geometry, part philosophy about the nature of the universe, and part statement about the social behavior of humans.  it's excellent and you can read the whole thing online at the link below.
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2.5 km means 2500m\nso it is 2500/50=50 lengths\nAnswer: c
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Yes,It involves a 5x5 matrix.
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We live and experience four dimensions. three of space, forward and back, left to right and up and down. we also experience one dimension of time, forward time. the other 7 dimensions are coiled into tiny doughnut like shapes the best model do describe this is the callabai-yau model.\n\nI'm sure you were hoping for a bit more then "they are to tiny to experience" but that is how it is.