Khan Academy
Khan Academy: Area of a Circle
Find the area of a circle given its radius, diameter, or circumference. Students receive immediate feedback and have the opportunity to try questions repeatedly, watch a video or receive hints.
Texas Instruments
Texas Instruments: Math Today Coming Clean About Showering Time
In this activity using the USA TODAY Snapshot, "Coming clean about showering time," students will find the measures of central angles and arcs of a circle. They will use circumference, radius, concentric circles and degrees in a circle...
Khan Academy
Khan Academy: Radius and Diameter
Practice problems finding radius and diameter of a circle.
Khan Academy
Khan Academy: Radius and Diameter
Practice finding the radius and diameter of a circle using both vocabulary and visuals. Students receive immediate feedback and have the opportunity to try questions repeatedly, watch a video or receive hints.
TeachEngineering
Teach Engineering: Let's Take a Slice of Pi
Working as a team, students discover that the value of pi (3.1415926) is a constant and applies to all different sized circles. The team builds a basic robot and programs it to travel in a circular motion. A marker attached to the robot...
Alabama Learning Exchange
Alex: Arc Lengths and Sector Areas
Young scholars 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...
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.
Mocomi & Anibrain Digital Technologies
Mocomi: What Is Circle?
Discusses the radius, diameter, circumference, and area of a circle.
Wolfram Research
Wolfram Math World: Circle
This site from Mathworld provides a wealth of information about circles is presented. The information ranges from the basics--radius, circumference, etc.--to advanced concepts--equations in polar and pedal coordinates, etc.
Ducksters
Ducksters: Kids Math: Circle Geometry
Circle Geometry math for kids contains information for students to learn about terms radius, diameter, circumference, chord, and pi.
ClassFlow
Class Flow: Circles
[Free Registration/Login Required] This flipchart has information and practice regarding finding area and circumference of circles.
Oswego City School District
Regents Exam Prep Center: Area of Polygons and Circles
A lesson focusing on the area of polygons and the circumference of circles. Engaging, interactive practice worksheet, lesson plan, and related classroom activity complete this lesson.
Other
Simple Science: Slice of Pi
The interactive tutorial explores the history behind Pi and how to find its value. Students use images of circular objects and find the diameter and circumference to obtain an approximate value of Pi. The resource has an interactive...
University of Cambridge
University of Cambridge: Nrich: Watching the Wheels Go `Round and `Round
Use the formula for the circumference of a circle to solve the challenge of this problem. The solution is available at this one page website.
CK-12 Foundation
Ck 12: Circumference: Big Circle & Circle Units
[Free Registration/Login Required] Sudents use circle units to explore circumference in a big circle. Click challenge me to answer practice questions and click learn more to watch a video.
CK-12 Foundation
Ck 12: Circumference: Ancient Stonehenge Math Mysteries
[Free Registration/Login Required] Students change the length of a radius to explore the circumference of a circle. Click challenge me to answer practice questions and click learn more to watch a video.
CK-12 Foundation
Ck 12: Circumference vs. Radius
[Free Registration/Login Required] Students use the points on a circle to explore circumference and radius. Click challenge me to answer practice questions and click learn more to watch a video.
McGraw Hill
Glencoe Mathematics: Online Study Tools: Self Check Quiz on Circles
Students show comprehension of advanced mathematics skills in Geometry. The questions check understanding on circles. Topics include diameters, angles, and finding the circumference.
Khan Academy
Khan Academy: Arc Length
Relate the length of an arc to the circumference of a whole circle and the central angle subtended by the arc. Students receive immediate feedback and have the opportunity to try questions repeatedly, watch a video or receive hints.
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.
Texas Instruments
Texas Instruments: 3.14159265
In this activity, students investigate the circumference of circles and learn about the irrational number Pi.
Illustrative Mathematics
Illustrative Mathematics: 7.g Stained Glass
In this lesson plan, 7th graders use formulas for area and circumference to solve the word problem.
Ministry of Education and Universities of the Region of Murcia (Spain)
Ministerio De Educacion Y Ciencia: Tangencias
In Spanish. This interactive unit introduces various geometric concepts which are intended to be tools for solving problems of tangencies between straight lines, circles and points.
E-learning for Kids
E Learning for Kids: Math: World of Fish: Geometry
Students will play an interactive game to identify the circumference, radius, center, and diameter of circles.