Math2
Math2: Circles
This site has many useful formulas and examples relating to circles, including related definitions, circumference of a circle, area of a circle, length of a circular arc, area of a circular sector, equation of a circle in cartesian...
University of Cambridge
University of Cambridge: Nrich: Transformation Tease
Follow the directions at this one page website. You will get lots of practice plotting points on the coordinate grid and experience with transformational geometry.
Oswego City School District
Regents Exam Prep Center: Length of a Line Segment (Distance)
Use the coordinate plane and Pythagorean theorem to determine the length of a line segment. Click on the "Topic Index" to find a related practice exercise and teacher resource.
Curated OER
Circle Picture
This site provides definitions for different parts of a circle, pictures to more clearly represent formulas involving circles. Some of the formulas discussed include: area of a circle, area of a sector of a cirles, circumference, length...