October 04, 2022

Linear Pair of AnglesDefinition, Axiom, Examples

The linear pair of angles is a significant concept in geometry. With several real-world uses, you'd be astonished to figure out how useful this figure can be. Although you may think it has no use in your life, we all should understand the ideas to ace those examinations in school.

To save you time and offer this data readily accessible, here is an preliminary insight into the properties of a linear pair of angles, with diagrams and examples to guide with your private study sessions. We will also talk about few real-life and geometric uses.

What Is a Linear Pair of Angles?

Linearity, angles, and intersections are theories that exist to be applicable as you progress in geometry and more complicated theorems and proofs. We will answer this question with a straightforward definition in this unique point.

Definition

A linear pair of angles is the term provided to two angles that are located on a straight line and the total of their angles measure 180 degrees.

To put it simply, linear pairs of angles are two angles that are aligned on the same line and pair up to form a straight line. The total of the angles in a linear pair will at all times produce a straight angle equivalent
times to 180 degrees.

It is crucial to note that linear pairs are at all times at adjacent angles. They share a common vertex and a common arm. This means that at all times make on a straight line and are always supplementary angles.

It is crucial to make clear that, even though the linear pair are constantly adjacent angles, adjacent angles aren't always linear pairs.

The Linear Pair Axiom

Through the precise explanation, we will study the two axioms critical to fully understand any example thrown at you.

First, let's define what an axiom is. It is a mathematical postulate or assumption that is approved without having to prove; it is believed evident and self-evident. A linear pair of angles has two axioms connected with them.

The first axiom implies that if a ray is located on a line, the adjacent angles will create a straight angle, also known as a linear pair.

The second axiom states that if two angles produces a linear pair, then uncommon arms of both angles create a straight angle among them. This is commonly called a straight line.

Examples of Linear Pairs of Angles

To envision these axioms better, here are some figure examples with their individual explanations.

Example One

In this instance, we have two angles that are next to each other. As you can notice in the image, the adjacent angles form a linear pair since the total of their measures equals 180 degrees. They are also supplementary angles, as they share a side and a common vertex.

Angle A: 75 degrees

Angle B: 105 degrees

Sum of Angles A and B: 75 + 105 = 180

Example Two

In this instance, we have two lines intersect, producing four angles. Not all angles creates a linear pair, but each angle and the one close to it form a linear pair.

∠A 30 degrees

∠B: 150 degrees

∠C: 30 degrees

∠D: 150 degrees

In this case, the linear pairs are:

∠A and ∠B

∠B and ∠C

∠C and ∠D

∠D and ∠A

Example Three

This instance presents convergence of three lines. Let's observe the axiom and characteristics of linear pairs.

∠A 150 degrees

∠B: 50 degrees

∠C: 160 degrees

None of the angle totals add up to 180 degrees. As a consequence, we can come to the conclusion that this figure has no linear pair unless we extend a straight line.

Applications of Linear Pair of Angles

Now that we have explored what linear pairs are and have observed some cases, let’s understand how this concept can be applied in geometry and the real world.

In Real-Life Scenarios

There are many applications of linear pairs of angles in real-world. One common example is architects, who apply these axioms in their day-to-day job to identify if two lines are perpendicular and form a straight angle.

Construction and Building professionals also use masters in this subject to make their job less complex. They use linear pairs of angles to ensure that two adjacent walls make a 90-degree angle with the floor.

Engineers also uses linear pairs of angles frequently. They do so by working out the tension in beams and trusses.

In Geometry

Linear pairs of angles also perform a role in geometry proofs. A common proof that employs linear pairs is the alternate interior angles theorem. This theorem expresses that if two lines are parallel and intersected by a transversal line, the alternate interior angles made are congruent.

The proof of vertical angles additionally depends on linear pairs of angles. Although the adjacent angles are supplementary and add up to 180 degrees, the opposite vertical angles are always equal to each other. Because of previously mentioned two rules, you only need to determine the measure of one angle to determine the measure of the rest.

The theorem of linear pairs is also utilized for more complex applications, such as measuring the angles in polygons. It’s critical to understand the fundamentals of linear pairs, so you are ready for more advanced geometry.

As you can see, linear pairs of angles are a comparatively easy theorem with some engaging applications. Next time you're out and about, see if you can spot any linear pairs! And, if you're taking a geometry class, take notes on how linear pairs may be helpful in proofs.

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