Quia
Ixl Learning: Area of Circles
Brush up on your math skills relating to the area of circles then try some practice problems to test your understanding.
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.
BBC
Bbc: Circumference and Area of a Circle
This is where you can pick up some valuable pointers on how to find the circumference and area of a circle. There is also information on how to find the perimeter and area of a semicircle. When you finish working your way through the...
Illustrative Mathematics
Illustrative Mathematics: G Gmd Circumference of a Circle
For this task, students are asked to explain the formula for finding the circumference of a circle. Aligns with G-GMD.A.1.
Discovery Education
Discovery Education: Web Math: Find Out Things About Circles
This WebMath site will assist with finding the radius, diameter, circumference, and area of a circle.
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.
Math Open Reference
Math Open Reference: Circles
A complete reference guide to circles including parts, angles, and arcs. It provides definitions and interactive activities that enhance further explanation.
Illustrative Mathematics
Illustrative Mathematics: G Gmd Area of a Circle
For this task, students investigate and develop an understanding of the formula for the area of a circle. Aligns with G-GMD.A.1.
Math Open Reference
Math Open Reference: Parts of a Circle
Learn about parts of a circle with this pictorial index. Click on the diagrams for more information. Includes links to related topics.
Math Open Reference
Math Open Reference: Area Enclosed by a Circle
A complete reference guide to the area enclosed by a circle. It provides definitions, examples, and an interactive activity that enhances further explanation. Includes links to related topics.
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.
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.
Calculator Soup
Calculator Soup: Circle Calculator
Use this circle calculator to find the area, circumference, radius, or diameter of a circle. Given any one variable A, C, r or d of a circle you can calculate the other three unknowns.
Mocomi & Anibrain Digital Technologies
Mocomi: What Is Circle?
Discusses the radius, diameter, circumference, and area of a circle.
Homeschool Math
Homeschool Math: Circles
Lesson presents definitions of terms associated with circles and helps students learn to use a compass to draw circles and simple circle designs.
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.
Other
Circles/circumference Interactive Learning Sites for Education
Includes record sheets and interactive media exploring circles and circumference from general parts of the circle to the relationship of the circle parts.
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...
ClassFlow
Class Flow: Area of a Circle
[Free Registration/Login Required] This flipchart reviews basic geometric forms in nature and real objects. Students are then given opportunities to find the area of circle and parts of a circle, given the radius and/or diameter of the...
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.
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.
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.
BBC
Bbc: Bitesize: Maths: 2 D Shapes
Learn about the properties of 2-D shapes: circles, triangles, polygons, and quadrilaterals. Includes information, video, and examples about each, with games and quizzes for reinforcement.