Finding volume with polar coordinate.

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Discussion Overview

The discussion revolves around estimating the volume of an irregular shape defined by a set of points in polar coordinates (r, theta, z). Participants explore methods for calculating volume without explicit formulas or equations, focusing on the challenges posed by the irregularity of the shape.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested
  • Mathematical reasoning

Main Points Raised

  • One participant notes the absence of formulas and seeks advice on estimating volume from given polar coordinates.
  • Another participant suggests visualizing the points as forming an irregular hexagon and questions whether the vertical sides are flat or curved, proposing the area of the hexagon times the average height as a potential method.
  • A third participant expresses frustration over the lack of guidance from their professor and contemplates guessing the volume, echoing the previous suggestion of using area and height.
  • One participant shares a drawing to aid visualization and mentions the possibility of a cylindrical surface.
  • In a follow-up, a participant introduces additional points that alter the shape from a cylinder to an irregular form, likening it to a sand clock shape and requesting a visual representation of the new points overlaid on the previous drawing.

Areas of Agreement / Disagreement

Participants do not reach a consensus on a method for estimating the volume, with multiple competing views on how to interpret the shape and calculate the volume based on the provided points.

Contextual Notes

Participants express uncertainty regarding the assumptions about the shape's geometry and the appropriateness of various volume estimation methods given the irregularity of the data.

isdouble
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The question I have is a bit strange.
I do not have ANY formulas or equations given.
I was only given bunch of points with r, theta, and z. Z being the depth. R being radius and Theta being the angle.
I was wondering if there is a way to find a rough estimate volume of the following.
R Theta Z
0.5 0 0
0.4 60 0.1
0.3 120 0
0.4 180 0.2
0.5 240 0
0.4 300 0
0.5 0 3
0.4 60 3.1
0.3 120 3.1
0.4 180 3
0.5 240 3.2
0.4 300 2.9

Of course I tried using triple integral method but was immediately out the window since there is no equations to input. Any advice would be great. Thank you.
Oh BTW, this is a irregular shape so I cannot link it to any common shapes either..
 
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It looks like you have 6 points around the bottom and top. If you look straight down at these points you see an irregular hexagon shape. Are the vertical sides assumed to be flat between the given points like a hexagonal cylinder or are the sides curved and just pass through the six points of the hexagon shape? I'm thinking you could take the area of the hexagon projection times the average height maybe? What else do you know about the shape?
 
I got nothing. My prof just gave me these points and told me to find an estimated volume by using Excel VBA but I can't even use the VBA if I can't even solve the problem on paper. She told me there is no right or wrong answer so am I suppose to just guess what it's suppose to be? I was thinking about the same as you but that would be my last choice. Thanks for your input.
 
Here's a picture. The scale on the vertical axis is compressed. One could certainly imagine a cylinder like surface.

points.jpg
 
That's one part. I forgot to mention the second part. BTW thanks for the drawing. It's really helping. So for part 1, I'm going to assume that its a cylinder and use the volume formula to find it. For part B, there are more points added to the original.
R Theta Z
0.55 0 0.4
0.45 60 0.6
0.35 120 1
0.45 180 0.8
0.55 240 1
0.45 300 1.5
0.45 0 1.9
0.35 60 2.1
0.25 120 2.5
0.35 180 2
0.45 240 2
0.35 300 2
Now it changed the form from cylinder into a irregular shape.
I can kind of visualize it like a sand clock shape. (I think?)
I'm sorry but can you draw these points on top of the ones you drew previously?
That would help me visualize better.
Thank you.
 
isdouble said:
Now it changed the form from cylinder into a irregular shape.
I can kind of visualize it like a sand clock shape. (I think?)
I'm sorry but can you draw these points on top of the ones you drew previously?
That would help me visualize better.
Thank you.

This is probably pushing the boundary of how much I should do for you:

points2.jpg


Note that the lines aren't plotted in the order the points are given. You will have to sort that out.
 

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