Curated OER
Trigonometry Realms
Excellent site reviewing the realms of Trigonometry. Topics Include the trig functions, graphs, right triangles and much more.
Science Buddies
Science Buddies: Throwing You Some Curves: Is Red or Blue Longer?
This a straightforward, but interesting, project in geometry. It is a good first proof to try on your own. You should be able to figure it out by yourself, and you'll gain insight into a basic property of circles.
Oswego City School District
Regents Exam Prep Center: Circles
Use this lesson, practice quiz, and activity when planning classroom instruction on graphs and equations of circles.
![Pbs Mathline: Bubble Mania Lesson Plan [Pdf] Lesson Plan](https://d15y2dacu3jp90.cloudfront.net/images/attachment_defaults/resource/large/FPO-knovation.png "Pbs Mathline: Bubble Mania Lesson Plan [Pdf] Lesson Plan")
PBS
Pbs Mathline: Bubble Mania Lesson Plan [Pdf]
Determine the area, diameter, and circumerfence of a bubble residue by creating a soap solution and blowing bubbles.
Government of Alberta
Learn Alberta: Math Interactives: Exploring Circle Geometry Properties
Investigate circles, namely their angles, chords, and tangents using this highly interactive Learn Alberta math. Explore a number of circle geometry properties that can be used to determine unknowns. Be sure to follow the link to the...
McGraw Hill
Glencoe: Self Check Quizzes 2 Circles and Circumference
Use Glencoe's Math Course 2 randomly generated self-checking quiz to test your knowledge of circles and circumference. Each question has a "Hint" link to help. Choose the correct answer for each problem. At the bottom of the page click...
Unite for Literacy
Unite for Literacy: Know and Learn: I See a Circle
A book about circles in the world around us. Includes audio narration in 6 additional languages with text in English.
Texas Education Agency
Texas Gateway: Making Conjectures About Circles and Angles
Given examples of circles and the lines that intersect them, the student will use explorations and concrete models to formulate and test conjectures about the properties of and relationships among the resulting angles.
Varsity Tutors
Varsity Tutors: Hotmath: Practice Problems: Circle Exercises
Twenty-five problems cover various circle activities. They are given with each step to the solution cleverly revealed one at a time. You can work each step of the problem then click the "View Solution" button to check each step of your...
Texas Education Agency
Texas Gateway: Using Logical Reasoning to Prove Conjectures About Circles
Given conjectures about circles, the student will use deductive reasoning and counterexamples to prove or disprove the conjectures.
Varsity Tutors
Varsity Tutors: Hotmath: Practice Problems: Circles
Twenty-three problems present a variety of practice working with various aspects of circles. They are given with each step to the solution cleverly revealed one at a time. You can work each step of the problem then click the "View...
Oswego City School District
Regents Exam Prep Center: Circles, Segments, and Area
A wealth of resources to supplement instruction on parts of the circle. Find lessons describing chords, tangents, secants, and segments, as well as related practice quizzes and classroom activities.
Oswego City School District
Regents Exam Prep Center: Circles and Angles
A wealth of material to supplement classroom instruction on circles, angles in circles, and arcs. Find lessons with formulas, diagrams, and example problems with step-by-step solutions, multiple-choice practice quizzes, and activity...
Paul Dawkins
Paul's Online Notes: Algebra: Circles
Detailed math tutorial features notes and examples that illustrate graphing circles.
Math Open Reference
Math Open Reference: Constructions
Learn about drawing shapes using only a compass and straight edge or ruler with out measuring any lengths or angles.
CK-12 Foundation
Ck 12: Geometry Software for Constructions
[Free Registration/Login Required] Students explore the concept of using geometry software to construct geometric shapes by navigating through the interactive learning module and then answering questions that go along with the module....
Science Buddies
Science Buddies: Thinking in (Semi )Circles: The Area of the Arbelos
The arbelos is the white-shaded region between the three semicircles in the illustration at right. In this project, you'll prove an interesting method for determining the area of the arbelos.
Cuemath
Cuemath: Circles
Explore everything about circles. Learn various parts of a circle like a diameter, radius, circumference, circles chord, tangent circles, major arc, segment, sector, and discover other interesting aspects of it. Try your hand at solving...
Cuemath
Cuemath: Diameter
Understand the concept of diameter by learning the definition and symbols. Check-out the solved examples for better understanding and try your hand at solving a few interactive questions at the end of the page.
Cuemath
Cuemath: What Is Pi?
Learn all about pi. This lesson targets what is pi, the pi symbol, the pi number, and the pi circle in the concept of what is pi. Check-out the interactive simulations to know more about the lesson and try your hand at solving a few...
Cuemath
Cuemath: Arc Length
Learn all about arc length. This lesson targets what is arc length and the different formulas used to calculate it. Check-out the interactive simulations to know more about the lesson and try your hand at solving a few interesting...
Cuemath
Cuemath: Central Angle
Learn all about the basic properties of central angles. This lesson targets what is a central angle, central angle formula, central angle calculator, theorem of central angle, how to find central angles, and how to apply them while...
OER Commons
Oer Commons: Measuring Circles
Seventh graders will measure the circumference and diameter of round things in the classroom and discover the ratio pi. They will see that the ratio of a circle's circumference to its diameter can be used to solve for the circumference...
Math Drills
Math Drills: Measurement Worksheets
Download these free worksheets to sharpen your measurement skills. Sheets focus on temperature, conversion, area and perimeter, volume, and more.