In Maths, a directly angle is one angle equal to 180 degrees. It is called straight due to the fact that it appears as a right line. Basically, together per angles definition in maths, as soon as two rays are joined end to end, they type an angle. Hence, the two rays the the 180-degree angle are subtended towards the the contrary direction, wherein the rays room joined to each various other at endpoints.

You are watching: What is the measure of a straight angle

In radians, the 180-degree angle is measured in pi (π). To point the the contrary way, the directly angle changes the direction. A 180 degree is likewise considered as supplementary. Except this angle, over there are 5 different species of angles in geometry i m sorry you can learn here.

Facts:A directly angle constantly forms a right line.The value of the straight angle is 180°.The eight of the right angle lied opposite come each other from the peak point.The directly angle measure up anticlockwise is the positive straight edge i.e.180°.The right angle measure clockwise is a an unfavorable straight angle i.e.-180°.

Straight angle Definition

In geometry, a straight angle is an angle, whose vertex point has a worth of 180 degrees. Basically, it creates a right line, whose political parties lie in opposite directions from the vertex. That is likewise termed as “flat angles”


A horizontal line and also a vertical heat are constantly straight lines and therefore they are instances of right angles.


In degrees, the right angle is represented as 180° and in radians, that is denoted v pi (π).

Straight angle Examples

Some the the straight angle examples in ours day-to-day life are:

A level surface has actually an angle of 180 degreesA straight stick has an angle which is straight or 180 degreeA aircraft inclined staircase represents a straight angleAngle formed in a see-saw

A right angle is various from the right line, as it procedures 180 degrees and a right line is a connector of two points.


Straight angle theorem says that every the directly angles are 180 degrees. If the legs of angle, space pointing exactly in the opposite directions, then it creates a right angle. A right angle is stood for as 180° (in degrees) or π (in radians).

One great example is the heat segment in geometry, the endpoints of i beg your pardon extends towards the opposite direction. 

Properties of directly Angles

Some important properties of right angles room as follows:

A right angle procedures exactly half of a revolutionA directly angle is created by revolving one beam by 180° through respect to an additional rayIn a right angle, the arms extend in opposing directionsA straight angle modifies the direction that a pointA straight angle can also be created by joining two ideal angles

Six varieties of Angles

An edge is created when 2 line segments room joined in ~ a solitary endpoint or once two heat segments are combined at a single endpoint. The allude where the two lines fulfill is dubbed the vertex of the angle. There space basically 6 different types of angles whose peak values are different, respectively, and also they are;

Acute edge (less 보다 90°)Obtuse edge (more than 90°)Right edge (equal come 90°)Straight Angle 
(exact 180°)Reflex edge (greater 보다 180°) and also Full angle (Exact 360°)

An angle v 0° is dubbed a zero angle, method it doesn’t type an angle. These are the general category of angles.

In geometry, we compare 2 angles based upon their conditions. Some angles are defined in terms of their similarity, called as a congruent angle, which has the very same angle. Then, us have surrounding angles, i beg your pardon are adjacent to every other. Security angles, whose sum is same to 90°.

Can we take into consideration a Triangle made from a right Angle?

A straight angle has a measure up of 180°and the sum of inner angles the a triangle is additionally 180°. However we cannot take into consideration straight angle together a straight angle triangle because, for a triangle, the number should form an fastened structure.

Triangle is a closeup of the door three-sided figure, which has three distinct points which room not collinear v each other. But, in the situation of the directly line, the points space collinear and hence castle cannot kind a closed structure. Therefore, there is no triangle formed.

How to construct a directly Angle?

The steps to build a right Angle, are as follows:

Draw a straight-line OB making use of a ruler, through an arrowhead in ~ BNow ar the protractor ~ above this heat such the the baseline the the protractor is readjusted over OB. The suggest B must be encountering towards the 0°of the protractor.Now note the point, beginning from 0° and also moving in the direction of 180 degrees. On reaching 180°, mark a suggest A top top the paper.Now, join the peak of the line OB with the significant point A. The 2nd ray OA should have actually arrowhead in ~ A.

See more: Why Did Kratos Kill His Family ? Why Did Kratos Want To Kill All The Gods


A directly angle is one angle equal to 180 degrees. That looks like a straight line. In radian, that is measured as π angle.