October 04, 2022

Linear Pair of AnglesDefinition, Axiom, Examples

The linear pair of angles is an essential concept in geometry. With several real-life uses, you'd be astonished to find how relevant this figure can be. Although you might believe it has no relevant in your life, we all must grasp the ideas to nail those exams in school.

To save you time and create this info easily accessible, here is an introductory insight into the properties of a linear pair of angles, with images and examples to guide with your private study sessions. We will also talk about some real-life and geometric uses.

What Is a Linear Pair of Angles?

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

Definition

A linear pair of angles is the name given to two angles that are situated on a straight line and have the sum of their angles measure 180 degrees.

To put it easily, linear pairs of angles are two angles that are aligned 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 make a straight angle equal 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 they always create 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

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

Let’s start by defining what an axiom is. It is a mathematical postulate or hypothesis that is approved without proof; it is believed clear and self-explanatory. A linear pair of angles has two axioms connected with them.

The first axiom establishes that if a ray stands on a line, the adjacent angles will make a straight angle, namely called a linear pair.

The second axiom establishes that if two angles create a linear pair, then uncommon arms of both angles makes 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 some figure examples with their corresponding answers.

Example One

In this instance, we have two angles that are next to each other. As you can observe in the figure, the adjacent angles form a linear pair since the sum of their measures 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 possess two lines intersect, making four angles. Not all angles makes 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 represents an intersection of three lines. Let's look at 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 image has no linear pair unless we expand one straight line.

Implementations of Linear Pair of Angles

At the moment we have gone through what linear pairs are and have observed some cases, let’s understand how this theorem can be utilized in geometry and the real-life scenario.

In Real-Life Scenarios

There are several implementations of linear pairs of angles in real life. One common case is architects, who use these axioms in their daily job to establish if two lines are perpendicular and creates a straight angle.

Builders and construction professionals also utilize masters in this subject to make their work easier. They utilize linear pairs of angles to ensure that two adjacent walls create a 90-degree angle with the floor.

Engineers also utilizes linear pairs of angles regularly. They do so by working out the pressure on the beams and trusses.

In Geometry

Linear pairs of angles also play a role in geometry proofs. A regular proof that utilizes linear pairs is the alternate interior angles concept. 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 additionally depends on linear pairs of angles. Even though the adjacent angles are supplementary and add up to 180 degrees, the opposite vertical angles are at all times equal to one another. Because of these two rules, you are only required to determine the measure of any one angle to figure out the measure of the rest.

The theorem of linear pairs is further employed for more complicated uses, such as figuring out the angles in polygons. It’s essential to grasp the basics of linear pairs, so you are ready for more advanced geometry.

As you can see, linear pairs of angles are a relatively simple theorem with some interesting applications. Later when you're out and about, observe if you can notice some linear pairs! And, if you're attending a geometry class, bear in mind how linear pairs may be helpful in proofs.

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