U+221D Proportional To
U+221D was added in Unicode version 1.1 in 1993. It belongs to the block
This character is a Math Symbol and is commonly used, that is, in no specific script.
The glyph is not a composition. Its width in East Asian texts is determined by its context. It can be displayed wide or narrow. In bidirectional text it acts as Other Neutral. When changing direction it is mirrored. If its East Asian Width is “narrow”, U+221D forms a word with similar characters, which prevents a line break inside it. Otherwise it allows line breaks around it, except in some numeric contexts.
The CLDR project calls this character “proportional” for use in screen reading software. It assigns these additional labels, e.g. for search in emoji pickers: proportionality.
The Wikipedia has the following information about this codepoint:
In mathematics, two sequences of numbers, often experimental data, are proportional or directly proportional if their corresponding elements have a constant ratio. The ratio is called coefficient of proportionality (or proportionality constant) and its reciprocal is known as constant of normalization (or normalizing constant). Two sequences are inversely proportional if corresponding elements have a constant product, also called the coefficient of proportionality.
This definition is commonly extended to related varying quantities, which are often called variables. This meaning of variable is not the common meaning of the term in mathematics (see variable (mathematics)); these two different concepts share the same name for historical reasons.
Two functions $f\left(x\right)$ and $g\left(x\right)$ are proportional if their ratio $\frac{f\left(x\right)}{g\left(x\right)}$ is a constant function.
If several pairs of variables share the same direct proportionality constant, the equation expressing the equality of these ratios is called a proportion, e.g., a/b = x/y = ⋯ = k (for details see Ratio). Proportionality is closely related to linearity.
Representations
System  Representation 

Nº  8733 
UTF8  E2 88 9D 
UTF16  22 1D 
UTF32  00 00 22 1D 
URLQuoted  %E2%88%9D 
HTML hex reference  ∝ 
Wrong windows1252 Mojibake  âˆ 
HTML named entity  ∝ 
HTML named entity  ∝ 
HTML named entity  ∝ 
HTML named entity  ∝ 
HTML named entity  ∝ 
Encoding: EUCKR (hex bytes)  A1 F0 
Encoding: JIS0208 (hex bytes)  A2 E7 
L^{A}T_{E}X  \propto 
Adobe Glyph List  proportional 
digraph  0( 
Elsewhere
Complete Record
Property  Value 

1.1 (1993)  
PROPORTIONAL TO  
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Mathematical Operators  
Math Symbol  
Common  
Other Neutral  
Not Reordered  
none  


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Any  
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0  
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None  
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NA  
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Yes  
Yes  


Yes  


Yes  
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None  
ambiguous  
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—  
No_Joining_Group  
Non Joining  
Ambiguous (Alphabetic or Ideographic)  
none  
not a number  


R 