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Andras

  • 2 years ago

Can someone give a proof for this theorem? The circle has the largest area of all shapes, given a fixed perimeter.

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  1. henpen
    • 2 years ago
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    Not a formal proof, but here's the intuition. Imagine a cube, with a centre point. From this point radiate lines that touch the vertices of the cube. Sections such as these|dw:1350744197439:dw| are formed. The area of any pyramid is 1/3 * base area * height. As you add sides to the polyhedron, the height increases, so the volume increases.

  2. henpen
    • 2 years ago
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    |dw:1350744302510:dw|

  3. henpen
    • 2 years ago
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    The total base area for the whole shape is held constant by the requirements of your question,

  4. henpen
    • 2 years ago
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    This proof is in 3D, 2D is much easier, but uses the same logic.

  5. Andras
    • 2 years ago
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    Sorry but this didnt help much. How is this cube related to a circle or a sphere?

  6. Andras
    • 2 years ago
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    I guess the proof for 3D + sphere is similar to the 2D and circle. But how does this cube section help?

  7. henpen
    • 2 years ago
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    It is the starting point: as you increace the number of faces, the volume goes up

  8. estudier
    • 2 years ago
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    http://www.math.utah.edu/~treiberg/isoperim/isop.pdf

  9. Andras
    • 2 years ago
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    thanks

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