The Mathematical Symbol "Angle (∠)"

Exploring the ∠ Symbol in Mathematics

The mathematical symbol ∠ is universally recognized as representing an "angle". Predominantly used in geometry and trigonometry, this symbol denotes the shape formed by two rays, called the sides of the angle, sharing a common endpoint, termed the vertex of the angle. Let's delve into two primary uses of this symbol, providing two examples for each context.

1. Geometry

In geometry, ∠ is utilized to represent the measure or magnitude of the angle formed between two intersecting lines or line segments.

  • Example 1: If you have two intersecting lines forming an angle of 90 degrees, it is often written as ∠A = 90°, where A is the vertex of the angle.
  • Example 2: When two line segments, AB and BC, meet at point B forming an angle of 45 degrees, it can be represented as ∠ABC = 45°.

2. Trigonometry

In trigonometry, the ∠ symbol is commonly used to refer to angles in relation to trigonometric functions such as sine, cosine, and tangent.

  • Example 1: If you're trying to find the sine of a 30-degree angle, it might be written as sin(∠A) = 0.5, where ∠A = 30°.
  • Example 2: The tangent of a 45-degree angle is often denoted as tan(∠B) = 1, where ∠B = 45°.

To conclude, the ∠ symbol is versatile in mathematics, predominantly signifying angles. Whether indicating the magnitude of geometric angles or serving as a reference for trigonometric functions, the symbol is indispensable in many mathematical contexts.

Mathematical symbol 'Angle'

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Codes for the ∠ Symbol

The Symbol
Alt CodeAlt 8736
HTML Code∠
HTML Entity∠
CSS Code\2220
Hex Code∠

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 8736. 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: &#8736;</b>My symbol: ∠

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

HTML TextOutput
<b>My symbol: &ang;</b>My symbol: ∠

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

CSS and HTML TextOutput
span:after {
content: "\2220";}
<span>My symbol:</span>
My symbol: ∠

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

HTML TextOutput
<b>My symbol: &#x2220;</b>My symbol: ∠
On the assumption that you already have your canvas and the context set up, use the Hex code in the format 0x2220 to place the ∠ symbol on your canvas. For example:
JavaScript Text
const x = "0x"+"E9"
ctx.fillText(String.fromCodePoint(x), 5, 5);

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

The Unicode for ∠ is U+2220. 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:
[Hold down Alt]
[Press x]

(The 2220 turns into ∠. Note that you can omit any leading zeros.)
In JavaScript, the syntax is \uXXXX. So, our example would be \u2220. (Note that the format is 4 hexadecimal characters.)
JavaScript TextOutput
let str = "\u2220"
document.write("My symbol: " + str)
My symbol: ∠