Area of Circle Formula
The area of a circle is given by mutiplied by the circle constant (tau) multiplied by the radius of the circle squared.
Expression  Description 

The area of the circle.  
The circle constant (tau), where  
The radius of the circle. 
The area of a circle is given by multiplied by the circle constant (tau) multiplied by the radius of the circle squared. For example, to find the area of a circle with a radius of length the formula is:
The area of the circle with a radius of length is equal to units squared. The value can be substituted into the expression to calculate an area of approximately units squared.
The area of the circle formula can be using calculus^{[1]} or using a visual proof^{[2]}.

Derive Area of Circle Formula Example

Area of Circle Visual Proof Example