Wolfram Research
Wolfram Math World: Ellipsoid
This site from Math World begins with a picture of an ellipsoid and then gives cartesian and parametric equations for the surface. The site gives much more information for the ellipsoid, including special ellipsoids, a surface area...
Oswego City School District
Regents Exam Prep Center: General "Transformation" Vocabulary
This site offers a short discussion of transformations. The discussion has few pictures and expresses the transformations in terms of relative coordinates rather than pictures.
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...
Wolfram Research
Wolfram Math World: Octant
This page from MathWorld.com provides a good diagram of the eight octants of the Cartesian coordinate system. (Good picture, but not much explanation is included!)
Curated OER
Parametric Unit Circle
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...