Tag: euclid's fifth postulate

Questions Related to euclid's fifth postulate

Does Euclid' fifth postulate imply the existence of parallel lines? Explain

maths introduction to euclid's geometry euclid's fifth postulate conditional statements and converse euclid's postulates

  1. True

  2. False

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Correct Option: A
Explanation:

Yes, Euclid's fifth postulate is valid for parallelism of lines because, if a straight line $l$ falls on two straight lines $m$ and $n$ such that sum of the interior angles on one side of $l$ is two right angles, then by Euclid's fifth postulate the line will not meet on this side of $l$. 

Next, you know that the sum of the interior angles on the other side of line $l$ will also be two right angles. 
Therefore, they will not meet on the other side also. So, the lines $m$ and $n$ never meet and are, therefore, parallel.

The sum of angles of a triangle is _____

maths introduction to euclid's geometry euclid's fifth postulate conditional statements and converse euclid's postulates

  1. $180^\circ$

  2. $135^\circ$

  3. $90^\circ$

  4. $45^\circ$

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Correct Option: A
Explanation:

Sum of angles is given by the formula $(n-2) \times 180$,  where $n=no. of sides$

So, for triangle $n=3$, hence sum of angles$=180^o$

How many parallel lines can be drawn to a given line

maths introduction to euclid's geometry euclid's fifth postulate conditional statements and converse euclid's postulates

  1. $0$

  2. $1$

  3. $2$

  4. Infinite

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Correct Option: D
Explanation:

Infinite lines can be drawn parallel to a given line from Euclid's Postulates.

Which Euclid's postulate led to the discovery of several other geometries while attempting to prove it using other postulates and axioms
maths introduction to euclid's geometry euclid's fifth postulate conditional statements and converse euclid's postulates

  1. Fifth Postulate

  2. First Postulate

  3. Second Postulate

  4. Third Postulate

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Correct Option: A
Explanation:

Attempts to prove Euclid's Fifth Postulate using other postulates and axioms led to the discovery of several others geometries

State true or false:

Attempts to prove Euclid's fifth postulate using the other postulates and axioms led to the discovery of several other geometries.

maths introduction to euclid's geometry euclid's fifth postulate conditional statements and converse euclid's postulates

  1. True

  2. False

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Correct Option: B
Explanation:

If a straight line crossing two straight lines makes the interior angles on the same side less than two right angles, the two straight lines, if extended indefinitely, meet on that side on which are the angles less than the two right angles

this the fifth postulate,many tried to prove it but at the end they had to assume something which was very closely related to the fifth postulate,they didnot form any new geometries but from where they started they ended at the same point.
$B$

Select the correct answer. The three steps from solids to point are

maths introduction to euclid's geometry euclid's fifth postulate conditional statements and converse euclid's postulates

  1. Solids - surfaces - lines - points

  2. Solids - lines - surfaces - points

  3. Solids - surfaces - element - points

  4. Solids - elements - surfaces - points

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Correct Option: A
Explanation:

Euclid's Consider the three steps from solids to points (solids-surfaces-lines-points). In

each step we lose one extension, also called a dimension. So, a solid has three

dimensions, a surface has two, a line has one and a point has none. Euclid

summarized these statements as definitions.
Answer (A) Solids - surfaces - lines - points

Two distinct ________ lines cannot be parallel to the same line.

maths introduction to euclid's geometry euclid's fifth postulate conditional statements and converse euclid's postulates

  1. Intersecting

  2. Non-intersecting

  3. Parallel

  4. None of these

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Correct Option: A
Explanation:

Two intersecting lines cannot be parallel to same line as this statement is equivalent to Euclid's fifth postulate.

Select the correct statement for the following:

$A$: The angles of an equilateral triangle are equal.
$B$: Angles opposite to two congruent sides of a triangle are congruent.

maths axioms, postulates and theorems euclid's fifth postulate conditional statements and converse euclid's postulates

  1. $A$ is a theorem and $B$ is its corollary

  2. $B$ is a theorem and $A$ is its corollary

  3. $A$ and $B$ are both theorems

  4. $A$ and $B$ are both corollaries

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Correct Option: B
Explanation:

$B$ is called the  Triangle theorem.  $A$ can be proved using this theorem, as in an equilateral triangle, all sides are equal and the angles opposite to these congruent sides are Equal. So, $A$ is the corollary of $B$

A result in which the (usually short) proof relies heavily on a given theorem is known as 

maths axioms, postulates and theorems euclid's fifth postulate conditional statements and converse euclid's postulates

  1. Conjecture

  2. Corollary

  3. Lemma

  4. Axioms

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Correct Option: B
Explanation:

A result derived from a theorem is its corollary.

A proof is required for a :

maths axioms, postulates and theorems euclid's fifth postulate conditional statements and converse euclid's postulates

  1. Postulate

  2. Axiom

  3. Theorem

  4. Definition

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Correct Option: C
Explanation:

Axiom/Postulate — a statement that is assumed to be true without proof. These are the basic building blocks from which all theorems are proved. 


Theorem — a mathematical statement that is proved using rigorous mathematical reasoning.  In a mathematical paper, the term theorem is often reserved for the most important results.

So, the correct option is $C$ as a theorem needs a proof.