R Symbol
The latin letter r is used in math as a variable. It appears in geometric equations as a variable to represent the radius of a circle.
Symbol  Format  Data 

r  Unicode 

TeX 


SVG 
Usage
The circumference of a circle is given the constant τ (tau) multpilied by the radius of the circle, where τ = 2π.
The area of a circle is give by onehalf multiplied by τ (tau) mutliplied by the radius of the circle squared.
The Latin Alphabet is a collection of 26 symbols that form the basis of the English language. The alphabet's symbols are used throughout mathematics to represent variables, constants, and coeffecients.
Related Symbols
The capital Latin letter R is used in mathematics to represent the set of real numbers. Usually, the letter is presented with a "doublestruck" typeface when it is used to represent the set of real numbers.