## Who discovered the parallel postulate?

Euclid

Parallel postulate, One of the five postulates, or axioms, of Euclid underpinning Euclidean geometry.

### What is the major concept of the parallel line postulate?

The parallel postulate states that if a straight line intersects two straight lines forming two interior angles on the same side that add up to less than 180 degrees, then the two lines, if extended indefinitely, will meet on that side on which the angles add up to less than 180 degrees.

**Why are parallel postulates not proven?**

The parallel postulate says that if the angle measures of α and β add up to less than 180 degrees, then the dotted lines eventually intersect. Every attempt at proving the parallel postulate as a theorem was doomed to failure because the parallel postulate is independent from the other axioms and postulates.

**What is the 5th postulate and why is it special?**

This postulate is telling us a lot of important material about space. Any two points in space can be connected; so space does not divide into unconnected parts. And there are no holes in space such as might obstruct efforts to connect two points.

## What are the 5 postulates of Euclid?

Geometry/Five Postulates of Euclidean Geometry

- A straight line segment may be drawn from any given point to any other.
- A straight line may be extended to any finite length.
- A circle may be described with any given point as its center and any distance as its radius.
- All right angles are congruent.

### Does axioms Need proof?

Unfortunately you can’t prove something using nothing. You need at least a few building blocks to start with, and these are called Axioms. Mathematicians assume that axioms are true without being able to prove them. For example, an axiom could be that a + b = b + a for any two numbers a and b.

**Can the parallel postulate be proven?**

Every attempt at proving the parallel postulate as a theorem was doomed to failure because the parallel postulate is independent from the other axioms and postulates. We can formulate geometry without the parallel postulate, or with a different version of the postulate, in a way that adheres to all the other axioms.

**What is the problem with the 5th postulate?**

Far from being instantly self-evident, the fifth postulate was even hard to read and understand. 5. That, if a straight line falling on two straight lines… …the two straight lines, if produced indefinitely, meet on that side on which are the angles less than the two right angles.

## Which is the best proof of the parallel line postulate?

Proofs and Postulates: Triangles and Angles Parallel Line Postulate: If 2 parallel lines are cut by a transversal, then their coresponding angles are congruent. A simple sketch can show the parallel line postulate. note: moving each point the same distance and direction will produce a parallel line (and a coresponding angle)

### When do the dotted lines intersect the parallel postulate?

The parallel postulate says that if the angle measures of α and β add up to less than 180 degrees, then the dotted lines eventually intersect. Credit: 6054, via Wikimedia Commons.

**Which is a consequence of the Euclidean parallel postulate?**

One consequence of the Euclidean Parallel Postulate is the well- known fact that the sum of the interior angles of a triangle in Euclidean geometry is constant whatever the shape of the triangle. 2.2.1 Theorem. In Euclidean geometry the sum of the interior angles of any triangle is always 180°.

**Are there any axioms equivalent to the parallel postulate?**

Playfair’s axiom is simple and direct, but some of the most interesting statements that are equivalent to the parallel postulate involve triangles. You probably remember from high school geometry class that the angles of a triangle add up to 180 degrees. That is only true if you assume the parallel postulate.