A circle is a basic geometric shape that is used throughout mathematics. The shape plays an important role in trigonometry and the polar coordinate system. Formally, a circle is defined as a shape where every point along its perimeter is an equal distance from its center.
The radius is the distance from the center of the circle to any point along the perimeter of the circle.
The circumference, denoted with the variable , is the length around the perimeter of the circle.
The diameter is the distance between any two points along the perimeter of the circle that passes through the center of the circle.
The area of a circle is the amount of two-dimensional space that fits inside the perimeter of the circle.
The concept of a circle appears throughout math and its applications. There are two important circle constants that, when present in math equations and formulas, usually mean a circle is involved. The constants are (pi) and (tau). This website favors the circle constant (tau) over (pi). The circle constant is defined by the geometry of any circle as shown below:
Here are the basic geometric formulas relating to the circle.
The area of a circle is give by one-half multiplied by τ (tau) mutliplied by the radius of the circle squared.
The circumference of a circle is given the constant τ (tau) multpilied by the radius of the circle, where τ = 2π.
The standard form of a circle is given by the radius and center point of the circle.
The general form of the equation of a circle is given in terms of coeffecients.