October 04, 2022

Linear Pair of AnglesDefinition, Axiom, Examples

The linear pair of angles is an important subject in geometry. With multiple real-world uses, you'd be amazed to find how relevant this figure can be. While you might think it has no relevant in your life, we all must understand the ideas to nail those tests in school.

To save your time and offer this info readily accessible, here is an preliminary insight into the properties of a linear pair of angles, with images and examples to assist with your private study sessions. We will also talk about some real-life and geometric applications.

What Is a Linear Pair of Angles?

Linearity, angles, and intersections are concepts that remain to be useful as you move ahead with geometry and more complex theorems and proofs. We will answer this query with a straightforward definition in this single point.

Definition

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

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

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

It is crucial to make clear that, although the linear pair are constantly adjacent angles, adjacent angles not at all times linear pairs.

The Linear Pair Axiom

With the precise explanation, we will explore the two axioms earnestly to fully understand any example provided to you.

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

The first axiom establishes 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 makes a straight angle between them. In other words, they make a straight line.

Examples of Linear Pairs of Angles

To imagine these axioms better, here are some figure examples with their respective explanations.

Example One

In this instance, we have two angles that are next to one another. As you can see in the image, the adjacent angles form a linear pair since the sum of their measurement is equivalent to 180 degrees. They are also supplementary angles, since 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 possess two lines intersect, making four angles. Not all angles makes a linear pair, but respective angle and the one next to it form a linear pair.

∠A 30 degrees

∠B: 150 degrees

∠C: 30 degrees

∠D: 150 degrees

In this instance, 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 properties of linear pairs.

∠A 150 degrees

∠B: 50 degrees

∠C: 160 degrees

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

Implementations of Linear Pair of Angles

Now that we have learned what linear pairs are and have observed some instances, let’s check how this theorem can be utilized in geometry and the real world.

In Real-Life Situations

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

Builders and construction professionals also utilize experts in this field to make their job less complex. They use linear pairs of angles to make sure that two close walls make a 90-degree angle with the ground.

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

In Geometry

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

The proof of vertical angles as well replies on linear pairs of angles. While the adjacent angles are supplementary and sum up to 180 degrees, the opposite vertical angles are always equivalent to each other. Because of previously mentioned two rules, you only need to determine the measurement of any one angle to determine the measurement of the rest.

The theorem of linear pairs is further utilized for more complex implementation, such as determining the angles in polygons. It’s important to grasp the basics of linear pairs, so you are prepared for more progressive geometry.

As shown, linear pairs of angles are a comparatively simple theorem with some engaging applications. Next time you're out and about, take note if you can spot some linear pairs! And, if you're attending a geometry class, take notes on how linear pairs may be useful in proofs.

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