Proving an Angle Cannot Be Trisected w/ Compass & Ruler

  • Thread starter murshid_islam
  • Start date
  • Tags
    Angle
In summary, it is impossible to trisect an angle using only a compass and a ruler, as proven by ancient Greek mathematician Euclid. This is because the construction of an angle trisection requires the use of complex geometric constructions that go beyond the capabilities of a compass and a ruler. Additionally, the angle trisection problem is closely tied to the unsolvable task of duplicating a cube, making it a significant challenge in mathematics for centuries. Despite many attempts, no one has been able to find a solution to trisecting an angle with just a compass and a ruler, highlighting the limitations of these simple tools in solving complex mathematical problems.
  • #1
murshid_islam
458
19
i have read that it has been proven that an angle cannot be trisected using just a compass and a straight-edge (unless it is some specific angle, e.g., 90 degrees or 180 degrees). can anyone tell me where i can find the proof? can anyone suggest any website?
 
Mathematics news on Phys.org
  • #2
Buy an introductory book in algebra&group theory.
 
  • #4
murshid_islam said:
i have read that it has been proven that an angle cannot be trisected using just a compass and a straight-edge (unless it is some specific angle, e.g., 90 degrees or 180 degrees). can anyone tell me where i can find the proof? can anyone suggest any website?

If you are allowed to mark the straight edge with a pencil, then you can certainly trisect any acute angle. Of course, with marking not permitted you cannot.
 

Related to Proving an Angle Cannot Be Trisected w/ Compass & Ruler

1. Why can't an angle be trisected with a compass and ruler?

The construction of trisecting an angle with a compass and ruler has been proven impossible by mathematicians and geometricians for centuries. This is due to the fact that the trisection of an angle requires the construction of a length that is irrational, meaning it cannot be expressed as a simple fraction or decimal. Since a compass and ruler can only create lengths that are rational, it is impossible to trisect an angle with this method.

2. Is there a mathematical proof for why an angle cannot be trisected with a compass and ruler?

Yes, there is a mathematical proof for this, known as the Angle Trisection Theorem. This theorem states that it is impossible to construct an angle that is exactly one-third of another angle using only a compass and ruler.

3. Can an angle be trisected using other tools or methods?

Yes, there are other methods and tools that can be used to trisect an angle, such as using a protractor or a special tool called a trisector. However, these methods are not considered to be true compass and ruler constructions.

4. Are there any exceptions to the rule that an angle cannot be trisected with a compass and ruler?

No, there are no known exceptions to this rule. The Angle Trisection Theorem has been proven to hold true for all angles and cannot be circumvented by any means.

5. Why is it important to understand that an angle cannot be trisected with a compass and ruler?

Understanding this concept is important in mathematics because it teaches us about the limitations of certain tools and methods. It also helps to build a foundation for more advanced concepts and theorems in geometry. Additionally, knowing that an angle cannot be trisected with a compass and ruler can save time and effort when attempting to solve geometric problems.

Similar threads

Replies
17
Views
4K
Replies
7
Views
1K
Replies
16
Views
1K
  • Introductory Physics Homework Help
Replies
6
Views
1K
Replies
18
Views
1K
Replies
6
Views
2K
Replies
20
Views
3K
Replies
7
Views
2K
Replies
4
Views
2K
Replies
5
Views
3K
Back
Top