Element of 10cm divided into 3 equal parts?

SPV-SDIS69 -  
animostab Posted messages 3003 Registration date   Status Member Last intervention   -
Hello,

Several colleagues and I have a strange question...

We all know in mathematics that 10/3 = 3.333333333333333...

However, concretely, if we take an object, a piece of plastic for example, measuring 10.0 cm. We want to cut this piece of plastic into 3 equal parts.

- On one hand, is it mathematically and possibly technically feasible to cut this object into 3 equal parts?
- If it is possible to do so, what will be the measurements of each of the cut pieces? Given that the division above shows that the result tends toward infinity... But an object itself does not tend toward infinity, you understand what I mean?
- If it is impossible, why?

Thank you in advance for your help and for solving this quirky puzzle.

Bye.

Pierrick.
Configuration: Windows XP / Firefox 3.5.8

12 answers

  1. le père
     
    Hello

    3.3333... is not an infinite number in mathematics. It cannot be expressed with a finite number of digits in base 10, but if we were to write it in base 3 for example, it would simply be 10.1 with a single digit after the decimal point.
    On the other hand, 1/2, which is written as 0.5 in base ten, requires an infinite number of digits (0.1111111...) when written in base 3. And that doesn't mean that 1/2 is an infinite number. One must not confuse the (imperfect) representation of a number in a numeral system with the intrinsic value of the number.

    As for cutting a real object into three equal parts, it is neither more nor less difficult than cutting it into two! Mathematical equality only belongs to mathematicians, while the equality of real objects is always approximate.
    12
  2. 407
     
    It is very simple with a ruler and compass to divide a given length into three without worrying about irrational numbers since we do not do any calculations.
    The diseases of numbers are not transmissible to instruments (thankfully).
    So, if you do not know the method of Thales usually used, here is another one that is more related to Pythagoras.
    Draw the given segment (e.g., 10cm) and extend it by half (5cm).
    At the beginning of this segment (point a), draw a perpendicular line and mark your compass opening on it (5cm). Close it all to obtain a triangle abc, right-angled at (a). On the base of this triangle, which measures 15 cm, draw two perpendiculars (at 5cm intervals) that divide this base into three and connect to the hypotenuse.
    The largest of these two segments measures one third of 10 cm. (see the properties of isosceles triangles.)
    7
  3. lazer ninja
     
    First, you need to draw a perpendicular line to the segment
    then place the point on the side where you took the perpendicularity in the middle of a segment formed by the perpendicular line, thus forming an isosceles triangle. Then, you need to apply the property of medians to find the center of gravity, which is equal to two-thirds of the segment, allowing you to divide it accordingly.
    4
    1. animostab Posted messages 3003 Registration date   Status Member Last intervention   738
       
      Cutting 10 cm into 3 parts is like cutting hair into 4, especially if the sentence has no commas! Thanks for not digging up old posts that are useless here (webmaster).
      0
  4. Anonymous user
     
    tends towards infinity Ok but an object is finite, so with a tolerance (rounding)
    So if the same tolerance is applied to the 3 parts no problem they will be equal, same if you fold in 3
    2
  5. SPV-SDIS69
     
    Thank you for this information!!!

    So concretely, we could conclude that it is possible to divide an object of 10cm into 3 equal parts that would have a length of 10.1 in base 3 if I understand correctly?

    Thanks anyway.

    Bye.
    1
  6. SPV-SDIS69
     
    Re,

    There lies the entire problem we are facing. How can we obtain "finished" parts with mathematically infinite values?

    Thank you.

    Pierrick.
    0
  7. Anonymous user
     
    the universe is infinite but I have finished thinking (it tires me)
    1
  8. SPV-SDIS69
     
    Hi,

    Very well, hoping that others can provide me with more answers.

    Bye.
    0
  9. Zestyr Posted messages 503 Status Member 52
     
    In theory, it would be possible because it's a third of a value; if each share is 1/3, each part is equal!
    In practice, it's not possible because our tools do not allow us to do so. Moreover, it has no interest!

    --
    #define ZESTYR BOSS
    0
    1. Compteurazero.
       
      But it seems to me that we're going in circles not knowing the value of each 1/3. Also, 10.1 doesn't seem to me to be 10 as a comment said earlier.
      A piece of plastic divided into three equals three thirds, but are they equal in value?
      0
  10. charles1453 Posted messages 229 Status Member 17
     
    Hello,
    It is impossible to divide into 3 equal parts because that would mean assigning a finite decimal value to 4/3 since an object has finite dimensions.

    10/3 does not approach infinity; it approaches 10/3, but 10/0+ approaches infinity.

    a+
    0
  11. Flothebobcat Posted messages 1427 Status Member 55
     
    :S
    I have another mind-boggling topic like this
    If x created the universe and z created x who created z and so on ^^
    Does the universe actually have boundaries?
    --
    Best regards
    0
  12. Zestyr Posted messages 503 Status Member 52
     
    If z created x, then z existed before x, so it is impossible for x to have created z!

    Does the Earth have "borders"? As long as you don't fly over Afghanistan, you can keep going for a long time!
    --
    #define ZESTYR BOSS
    0