Rice University
Rice University: Cynthia Lanius: Circles Around Pythagoras
This site from the Rice University includes a fill-in-the-blank lesson on the definition of circles, as Pythagoras described.
Math Aids
Math Aids: Geometry
Great resource to practice and strengthen math skills pertaining to Geometry. Math worksheets are printable, may be customized, and include answer keys.
Math Is Fun
Math Is Fun: Definition of Circumference
Definition of circumference. Click the "here's more" link to learn more about a circle; its radius and diameter, area, lines, slices and common sectors.
Shmoop University
Shmoop: Basic Geometry: Area (Polygon, Triangle, Circle, Square)
The geometry resource investigates the area of polygons, triangles, circles, and squares. Formulas and examples are included.
Shmoop University
Shmoop: Basic Geometry: Area Formulas
The geometry resource investigates the area of polygons, triangles, circles, and squares. Formulas, examples, and practice exercises are included.
Wolfram Research
Wolfram Math World: Chord
Describes what a chord is and shows a diagram and shows how to find areas using integral calculus.
National Council of Teachers of Mathematics
The Math Forum: Ask Dr. Math: Area of a Cone
This question and answer site is about finding the area of a cone when the height and the angle at the convergence point are given. The site goes on to explain how a cone relates to a circle.
Illustrative Mathematics
Illustrative Mathematics: G Co Inscribing a Hexagon in a Circle
For this task, students inscribe a regular hexagon inside a circle and compare its area to that of the circle. Aligns with G-CO.D.13.
Other
Allmath: Math Glossary
Are your students having difficulty understanding math terminology? Try this A-Z glossary on math related terms. It's quick, easy to read, and very complete.
Alabama Learning Exchange
Alex: Arc Lengths and Sector Areas
Learners will work in cooperative groups to discover the relationships between arc length, central angle measure, and circumference. They will also discover the relationship between circle area, central angle measures, and sector area....
PBS
Pbs Learning Media: Formulas: Targeted Math Instruction
At the end of this lesson plan about formulas, young scholars will be able to identify and apply the correct formula for a given situation, solve for any unknown component of the formulas for perimeter, circumference, and area of regular...
Analyze Math
Analyze Math: Sectors and Circles Problems
Try these three problems regarding area of sectors, length of arcs, and central angles. The problems will challenge and intrigue sharp geometry students. Detailed written solutions are included.
Math Open Reference
Math Open Reference: Triangles
A complete reference guide to types of triangles and triangle perimeter and area. It provides definitions and interactive animated activities that enhance further explanation.
Ministerio de Educacion, Cultura y Deporte (Spain)
Cnice: Relacion De Ejercicios Interactivos.
In Spanish. Interactive activities online on various geometric and trigonometric concepts such as area, perimeter, secants, tangents, etc. A terrific resource for students. Site is organized acoording to shape. (triangle, quadrilaterals,...
Annenberg Foundation
Annenberg Learner: Math in Daily Life: Home Decorating
This exhibit is designed to show students that geometry really does apply to the real world. By taking viewers through a home decoration project, students learn how to calculate area of a rectangle and circle.