Symbol  Format  Data 

C  Code Point 
U+0043 
TeX 
C 

SVG 
The capital Latin letter C is used in mathematics as a variable. For example, it appears in geometric formulas as a variable representing the circumference of a circle.
The set of complex numbers is represented by the Latin capital letter C. The symbol is often presented with a doublestruck font face just as with other number sets. The set of complex numbers extends the real numbers.
The Latin small letter c is used in math to represent a variable, constant or coefficient.
A variable is a symbol that represents an unknown or indeterminant quantity. Variables can represent numbers, vectors, or other mathematical objects, depending on the context.
The circumference of a circle is given the constant τ (tau) multiplied by the radius of the circle, where τ = 2π.