Was ill a subject "the Circle " Help please with formulas, for example how to find C knowing R I how to solve such formula C = 2pr give please an example

With here length of a circle circle Length =2*pi*radius pi Number constant and is equal to a circle 3.14 we Receive length of a circle =2 * 3.14 * circle radius C=2 * 3.14 * R Just substitute
Answer add