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Angles in Three Dimensions

  1. Sep 27, 2011 #1
    We usually describe angles in two dimensions (x and y plane). What is the mathematics behind three dimensions?
  2. jcsd
  3. Sep 27, 2011 #2
    I don't get it. You're an undergrad in physics and you're asking this question? Why don't you already know?

    It's really no different. When you talk about the angle between things in three dimensions, you can think of them as being on some plane oriented in those three dimensions and then think about the angle in relation to that plane, just as you would with the familiar x-y plane...
  4. Sep 27, 2011 #3

    Char. Limit

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    Actually, I'd say we usually describe angles in two-dimensions with theta and r. That is, an angle from the designated "zero line", and a distance from the origin. In three dimensions, we simply add another angle, usually phi, that I call the "vertical angle", or the angle between the line and the x-y plane.
  5. Sep 27, 2011 #4
    I'm in Calculus based Classical Mechanics at the moment. We haven't gone into figuring out angles in three-dimensions.

    I'm surprised its that simple. I've read around and seen that sometimes the math isn't incredibly accurate (such as near pi with using cos).

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