CK-12 Foundation
Ck 12: Geometry: Radius or Diameter of a Circle Given Area
[Free Registration/Login may be required to access all resource tools.] Find the radius or diameter of a circle given its area.
CK-12 Foundation
Ck 12: Geometry: Circumference and Arc Length Study Guide
This study guide on circumference and arc length covers key vocabulary, the parts of a circle, and formulas for circumference, area, and arc length. It is available for download with free registration.
Texas Instruments
Texas Instruments: Circles: Circumference and Area
The idea of perimeter can be applied not only to polygons but to circles as well. The same idea can be said for the area of a circle. (Continued. See "before the activity.") [Requires Adobe Reader.]
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...
Math2
Math2: Circles
This site has many useful formulas and examples relating to circles, including related definitions, circumference of a circle, area of a circle, length of a circular arc, area of a circular sector, equation of a circle in cartesian...
Houghton Mifflin Harcourt
Holt, Rinehart and Winston: Homework Help Independent Practice: Circles
Get independent practice working with finding the circumference, area and radius of circles. Each incorrect response gets a text box explanation and another try. Correct responses are confirmed.
Mr. Martini's Classroom
Mr. Martini's Classroom: Circles Geometry Review
This resource provides two levels of multiple choice questions to review the parts of a circle as well as area and perimeter.
Cuemath
Cuemath: Area of a Circle
This mini-lesson explores the area of a circle. Provides a definition, examples, and practice questions with answers.
Khan Academy
Khan Academy: Area and Circumference of Circles Challenge
Practice interesting area and circumference problems. Students receive immediate feedback and have the opportunity to try questions repeatedly, watch a video or receive hints.
BBC
Bbc: Bitesize Review Circle Introduction
Do you need to learn about Pi, circumference, or the area of a circle or just have a quick refresher about them? This British web site will take you through the basics and offers a quick on-line test to help you check your understanding.
Mathigon
Mathigon: Geometry: Circle and Pi: Introduction
This lesson focuses on the characteristics of a circle including similarity, radius, circumference, and Pi. It provides formulas to determine the area of a circle, calculating Pi, and learning exercises throughout.
Khan Academy
Khan Academy: Praxis Core Math: Circles Lesson
A basic review of circles and how to calculate the circumference, radius, diameter, and area. Includes practice questions.
Other
Nearpod: Circles & Pi
In this lesson, 7th graders will learn vocabulary associated with circles and use formulas to find the area and circumference of circles.
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...
McGraw Hill
Glencoe Mathematics: Online Study Tools: Circumference and Area of Circles
This site gives a short interactive quiz which allows students to self-assess their understanding of the concept of finding the circumference and area of circles.
Thinkport Education
Math by Design: Circumference and Area of a Circle [Pdf]
Students will discover how to estimate and measure the 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.
Illustrative Mathematics
Illustrative Mathematics: 7.g the Circumference of a Circle and the Area
In this lesson plan, 7th graders determine the circumference and area of a circle.
Texas Instruments
Texas Instruments: Circle Around
In this activity, students compute the circumference and area of circles. They understand that the ratio of the circumference to the diameter is a value called pi. [Requires Adobe Reader.]
Texas Instruments
Texas Instruments: Arc Length and Area of Sectors
This is an introduction to finding the arc length and area of sectors of circles. Students should have the formulas for Circumference and Area of circles.
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.
Illustrative Mathematics
Illustrative Mathematics: 7.g Eight Circles
In this lesson plan, 7th graders use their knowledge of formulas to determine the area and circumference of a circle.
National Council of Teachers of Mathematics
The Math Forum: Elementary Geometry Circles
The Math Forum offers an archive of question and answer sessions on circles and how they relate to geometry.
Khan Academy
Khan Academy: Area and Circumference of Parts of Circles
In this exercise, students practice find the area and circumference, of parts of circles. Students receive immediate feedback and have the opportunity to get hints and try questions repeatedly.