October 04, 2022

Linear Pair of AnglesDefinition, Axiom, Examples

The linear pair of angles is a significant concept in geometry. With multiple real-life applications, you'd be amazed to figure out how applicable this figure can be. Although you may think it has no use in your life, we all must grasp the concept to ace those tests in school.

To save you time and create this information easily accessible, here is an introductory insight into the characteristics of a linear pair of angles, with visualizations and examples to guide with your private study sessions. We will also discuss few real-life and geometric uses.

What Is a Linear Pair of Angles?

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

Definition

A linear pair of angles is the term provided to two angles that are positioned on a straight line and have the sum of their measurement of angles is 180 degrees.

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

It is essential to bear in mind that linear pairs are always at adjacent angles. They share a common vertex and a common arm. This means that they always make on a straight line and are always supplementary angles.

It is crucial to explain that, while the linear pair are always adjacent angles, adjacent angles aren't always linear pairs.

The Linear Pair Axiom

Over the precise explanation, we will explore the two axioms critical to completely comprehend every example thrown at you.

Let’s start by defining what an axiom is. It is a mathematical postulate or assumption that is acknowledged without proof; it is deemed obvious and self-evident. A linear pair of angles has two axioms associated with them.

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

The second axiom states that if two angles create a linear pair, then uncommon arms of both angles produces a straight angle between them. This is also known as a straight line.

Examples of Linear Pairs of Angles

To imagine these axioms better, here are a few figure examples with their individual answers.

Example One

As we can see in this instance, we have two angles that are next to one another. As you can notice in the diagram, the adjacent angles form a linear pair because the sum of their measurement is equivalent to 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

Here, we have two lines intersect, making four angles. Not every angles creates a linear pair, but respective 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 a common point of three lines. Let's take note of the axiom and characteristics of linear pairs.

∠A 150 degrees

∠B: 50 degrees

∠C: 160 degrees

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

Implementations of Linear Pair of Angles

At the moment we have gone through what linear pairs are and have looked at some instances, let’s understand how this theorem can be implemented in geometry and the real world.

In Real-Life Situations

There are multiple applications of linear pairs of angles in real-world. One familiar case is architects, who utilize these axioms in their day-to-day work to establish if two lines are perpendicular and form a straight angle.

Construction and Building professionals also employ expertise in this subject to make their job easier. They use linear pairs of angles to make sure that two close walls create a 90-degree angle with the floor.

Engineers also utilizes linear pairs of angles regularly. They do so by calculating the weight on the beams and trusses.

In Geometry

Linear pairs of angles additionally play a function in geometry proofs. A regular proof that utilizes linear pairs is the alternate interior angles concept. This concept explains that if two lines are parallel and intersected by a transversal line, the alternate interior angles created are congruent.

The proof of vertical angles also replies on linear pairs of angles. While the adjacent angles are supplementary and add up to 180 degrees, the opposite vertical angles are always equal to each other. Because of above-mentioned two rules, you only need to determine the measure of any one angle to work out the measurement of the rest.

The theorem of linear pairs is further employed for more sophisticated applications, such as working out the angles in polygons. It’s essential to understand the fundamentals of linear pairs, so you are ready for more progressive geometry.

As demonstrated, linear pairs of angles are a relatively simple theorem with some interesting uses. Later when you're out and about, see if you can notice any linear pairs! And, if you're attending a geometry class, be on the lookout for how linear pairs may be useful in proofs.

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