Is the volume of an exemplary cone equal to 4/3(pi)?

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Discussion Overview

The discussion revolves around the calculation of the volume of a cone, specifically questioning the expression (4/27)*(3)^3 and whether it equals 4. Participants are examining the arithmetic involved in this calculation and addressing potential errors in understanding exponentiation and integer division.

Discussion Character

  • Technical explanation, Debate/contested, Mathematical reasoning

Main Points Raised

  • One participant questions the calculation of (4/27)*(3)^3, asserting that their evaluation leads to 4/3 instead of 4, and seeks clarification on where they might be wrong.
  • Another participant corrects the first by stating that 3^3 equals 27, not 9, implying that the initial arithmetic was flawed.
  • A later reply confirms that 3^3 is indeed 27 and supports the conclusion that the expression evaluates to 4.
  • Another participant introduces a programming perspective, noting that integer division in programming languages could lead to different results, emphasizing the importance of understanding how calculations are handled in different contexts.
  • One participant explains the order of operations, asserting that the expression can be correctly evaluated to equal 4, reinforcing the earlier corrections.
  • Another reiterates that 3^3 equals 27 and simplifies the expression to show that it indeed results in 4.

Areas of Agreement / Disagreement

Participants generally agree on the correct evaluation of the expression (4/27)*(3)^3 as equaling 4, but there are disagreements regarding the initial misunderstanding of the arithmetic and the implications of integer division in programming contexts.

Contextual Notes

There are limitations in the discussion regarding the assumptions made about arithmetic operations and the handling of integer versus floating-point calculations in programming, which remain unresolved.

5P@N
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How is (4/27)*(3)^3 = 4?

When I evaluate it as a first step, I reduce the (3)^3 into 9, thus generating:

(4/27) * 9.

With a little basic multiplication, I have:
36/27, or 4/3.
Which is obviously not equal to 4!

Am I right or wrong? Where did I make an error?

Take a look if you please at the answer the author of this article has given as regards the volume of an exemplary cone at the beginning of his page. Did he, or did he not make an error in his final calculation? Or am I wrong? My conclusion is that the volume is 4/3(pi).
 
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3^3 is not equal to 9 (are you thinking of 3*3 ?)
 
Oh. Oops. my bad.
 
A small glitch: 3^3 = 27 not 9. Then answer is indeed 4
 
5P@N said:
How is (4/27)*(3)^3 = 4?

When I evaluate it as a first step, I reduce the (3)^3 into 9, thus generating:

(4/27) * 9.
Apart from the arithmetic error: This will be wrong if you enter the formula in a C program (or any programming language that handles integers separate from floating point numbers). Assuming 4 and 27 to be integers, 4/27 is 0 (it has to be a non-negative integer less than 1). And even if you do 3^3 as a floating-point calculation, you still have the 0 from the first division...

Thus: when dealing with integers, (4/27)⋅3^3 ≠ (4⋅3^3)/27!
 
5P@N said:
How is (4/27)*(3)^3 = 4?
5P@N , the multiply and divide operation are an equal priority operation with left associativity. The power is right associative operation and it's priority is higher than multiply and divide operations. Thus the expression can be written as:
4/27*3^3
and it is really equals 4
 
Last edited by a moderator:
##3^3## is not equal to ##9##

##3^3=3×3×3=27##

##\dfrac{4}{27}×27\;\;\implies\dfrac{4}{\not27}×\not{27}=4##

I hope it' ll help.
 

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