Circles in the Coordinate Plane
The equation of a circle in a coordinate plane is written knowing the coordinates of its center and the length of the radius.
The equation of a circle of center (h,k) and radius r in standard form is: r² = (x-h)² + (y-x)²
The unit circle is the circle whose radius is equal to 1 and whose center is the origin.
Find out more about circles in the coordinate plane below.
Circles in the Coordinate Plane
Practice: Write equations of each circle that has a diameter with the given endpoints in the following exercises.