October 04, 2022

Linear Pair of AnglesDefinition, Axiom, Examples

The linear pair of angles is an essential concept in geometry. With so many real-life functions, you'd be astonished to figure out how applicable this figure can be. Even though you may wonder if it has no use in your life, we all should learn the concept to nail those exams in school.

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

What Is a Linear Pair of Angles?

Linearity, angles, and intersections are ideas that continue to be applicable as you progress in geometry and more sophisticated theorems and proofs. We will answer this question with a easy explanation in this unique point.

Definition

A linear pair of angles is the term provided to two angles that are situated 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 create a straight line. The total of the angles in a linear pair will always make a straight angle equal to 180 degrees.

It is important to keep in mind that linear pairs are always at adjacent angles. They share a common apex and a common arm. This suggests that they always make on a straight line and are always supplementary angles.

It is crucial to clarify that, even though the linear pair are always adjacent angles, adjacent angles not at all times linear pairs.

The Linear Pair Axiom

Through the precise explanation, we will examine the two axioms seriously to fully understand every example thrown at you.

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

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

The second axiom implies that if two angles produces 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 envision these axioms better, here are a few figure examples with their corresponding answers.

Example One

Here in this example, we have two angles that are adjacent to each other. As you can see in the image, the adjacent angles form a linear pair because the total of their measures is equivalent to 180 degrees. They are also supplementary angles, because 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, creating four angles. Not every angles creates a linear pair, but each angle and the one adjacent to it makes 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 observe the axiom and properties of linear pairs.

∠A 150 degrees

∠B: 50 degrees

∠C: 160 degrees

None of the angle combinations sum up to 180 degrees. As a result, we can come to the conclusion that this example has no linear pair unless we stretch one straight line.

Applications of Linear Pair of Angles

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

In Real-Life Scenarios

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

Builders and construction professionals also use masters in this field to make their work less complex. They use linear pairs of angles to assure that two adjacent walls create a 90-degree angle with the floor.

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

In Geometry

Linear pairs of angles additionally perform a function in geometry proofs. A regular proof that uses linear pairs is the alternate interior angles concept. This theorem states 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. Although the adjacent angles are supplementary and add up to 180 degrees, the opposite vertical angles are at all times equivalent to each other. Because of these two rules, you are only required to know the measurement of one angle to determine the measure of the rest.

The theorem of linear pairs is subsequently employed for more complex applications, such as working out the angles in polygons. It’s critical to grasp the basics of linear pairs, so you are prepared for more advanced geometry.

As demonstrated, linear pairs of angles are a comparatively easy concept with some engaging uses. Later when you're out and about, see if you can see some linear pairs! And, if you're taking a geometry class, be on the lookout for how linear pairs may be useful in proofs.

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