## The Mathematical Symbol "Right Angle (∟)"

The "Right Angle" Symbol (∟)

The ∟ symbol represents a "right angle" in geometrical contexts. In Euclidean geometry, a right angle is an angle of exactly 90°, corresponding to a quarter of the full circle.

## Usage of ∟

Right angles are a fundamental concept in geometry and trigonometry. Their properties have been understood and utilized since ancient times.

Example 1: In Rectangles

All four angles in a rectangle are right angles. Thus, if a quadrilateral has four right angles (as denoted by ∟), then it is a rectangle.

Example 2: Pythagoras' Theorem

In a right-angled triangle, the side opposite the right angle is called the hypotenuse. Pythagoras' theorem states that in a right-angled triangle, the square of the length of the hypotenuse is equal to the sum of the squares of the other two sides. If ∟ denotes the right angle, then the theorem can be represented as: c² = a² + b², where c is the length of the hypotenuse, and a and b are the lengths of the triangle's other two sides.

## Significance in Different Fields

Right angles have a wide range of applications:

• Architecture: Right angles are crucial in construction, ensuring structures are perpendicular and stable.
• Mathematics: They're foundational in geometry, trigonometry, and calculus.
• Astronomy: Right angle triangles aid in calculations involving the distances and sizes of celestial bodies.

In summary, the ∟ symbol is a simple yet powerful representation of a concept that has been essential in various disciplines throughout history. ## Are You Good at Mathematical Symbols?

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## Codes for the ∟ Symbol

 The Symbol ∟ Alt Code Alt 8735 HTML Code ∟ HTML Entity ∟ CSS Code \221F Hex Code ∟ Unicode U+221F

## How To Insert the ∟ Symbol

(Method 1) Copy and paste the symbol.

The easiest way to get the ∟ symbol is to copy and paste it into your document.

Bear in mind that this is a UTF-8 encoded character. It must be encoded as UTF-8 at all stages (copying, replacing, editing, pasting), otherwise it will render as random characters or the dreaded �.

(Method 2) Use the "Alt Code."

If you have a keyboard with a numeric pad, you can use this method. Simply hold down the Alt key and type 8735. When you lift the Alt key, the symbol appears. ("Num Lock" must be on.)

(Method 3) Use the HTML Decimal Code (for webpages).

HTML TextOutput
<b>My symbol: &#8735;</b>My symbol: ∟

(Method 4) Use the HTML Entity Code (for webpages).

HTML TextOutput
<b>My symbol: &angrt;</b>My symbol: ∟

(Method 5) Use the CSS Code (for webpages).

CSS and HTML TextOutput
<style>
span:after {
content: "\221F";}
</style>
<span>My symbol:</span>
My symbol: ∟

(Method 6) Use the HTML Hex Code (for webpages and HTML canvas).

HTML TextOutput
<b>My symbol: &#x221F;</b>My symbol: ∟
On the assumption that you already have your canvas and the context set up, use the Hex code in the format 0x221F to place the ∟ symbol on your canvas. For example:
JavaScript Text
const x = "0x"+"E9"
ctx.fillText(String.fromCodePoint(x), 5, 5);
Output

(Method 7) Use the Unicode (for various, e.g. Microsoft Office, JavaScript, Perl).

The Unicode for ∟ is U+221F. The important part is the hexadecimal number after the U+, which is used in various formats. For example, in Microsoft Office applications (e.g. Word, PowerPoint), do the following:
TypeOutput
221F
[Hold down Alt]
[Press x]

(The 221F turns into ∟. Note that you can omit any leading zeros.)
In JavaScript, the syntax is \uXXXX. So, our example would be \u221F. (Note that the format is 4 hexadecimal characters.)
JavaScript TextOutput
let str = "\u221F"
document.write("My symbol: " + str)
My symbol: ∟