# Plain angle

One of the most important fields of mathematics is known by the name of **geometry** , a science that is responsible for studying all the properties, shapes and measurements of space or the plane. Within this concept there are many definitions of great importance, one of them is the **angles** , spaces that exist between the **intersection** of two different lines. There are many types of angles, in this case, we will talk about the straight **angle** .

## What is a straight angle?

The **straight** angle, also known as the **plane angle** , is the portion of the same that is between two **rays** which are joined by means of a **vertex** that has an amplitude of **180 °.**

- Definition
- Characteristics of the shallow angle
- How much is a straight angle
- Which objects form a straight angle
- Examples

## Definition

The **angles** are one of the most fundamental parts of **mathematics** and can also be found in any area where the graphic elements are used. In geometric terms we can define the straight angle as the **space** that is included in an **intersection** that occurs between two lines in which there is an opening measuring **180 °.**

It can also be defined as the angle that has as sides two **rays** that are **opposite** , in other words, that they are **collinear** . It is also known by the name of **rectilinear angle** , this because this type of angle is present in straight lines and for this reason, it is in fact the easiest angle to remember.

## Characteristics of the shallow angle

The main characteristics of flat angles are the following:

- The straight angle has an exact measure of
**180 °**. - It has the ability to form a
**straight line**. - Your
**180 ° turn will**always end in the**opposite direction**. - It is considered as the limit that exists between
**convex angles**and**concave**angles . - It results from the
**sum**that occurs between**two right angles**. - It can be seen as
**half**of a**full angle**. - They have the ability to
**divide**a**circle**into two equal parts. - When the sum is given between an acute angle and an obtuse angle is equal to the measure of the straight angle, then these will become
**supplementary**angles . - When you
**change your address**, it will always be to the opposite side.

## How much is a straight angle

A straight angle has a measure of **180** ° and in order to measure it you need to use a **protractor** . It is possible to find this type of **measuring instrument** with an amplitude of the same measure that the flat angles have.

The way to measure it is very simple, the first thing to do is make a **ray** with the protractor, then the compass is opened from the **origin** until reaching the **end of the ray** and then a **180** ° **turn** must be drawn until reaching to the opposite side.

If you need to measure the **bisector** of the **straight** angle, this turns out to be a quieter procedure because at first glance, the 180 ° angle is a straight line, so you only need to determine its **central point** , the **vertex of** the two rays and then start to draw from that place a line **perpendicular** to both.

## Which objects form a straight angle

Some objects that can be found in daily life that form flat angles we mention the following:

- They can be observed in analog clocks when the hands of the clock form the time.
- When the arm is stretched or when the dancers make movements with their legs, flat angles can be formed.
- The horizon, whose opening is described by the curve produced by the sun.
- In the seesaws that children use to play, a flat angle can easily be observed.
- When the arm is fully stretched, this type of angle is formed.

## Examples

Other examples of straight angle are mentioned below:

- A table
- Half a watermelon
- A line drawn with a straight line
- A wall