Khan Academy
Khan Academy: Circumference of a Circle
Find the circumference of a circle when given either the radius or diameter.Find the radius or diameter of a circle when given the circumference.Students receive immediate feedback and have the opportunity to try questions repeatedly,...
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.]
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.
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.
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...
Texas Instruments
Texas Instruments: Perimeter, Circumference, and Area
Students find perimeters of rectangles and squares, as well as circumferences of circles. Students find areas of rectangles, squares, and circles. [Requires Adobe Reader.]
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: 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.
The Math League
The Math League: Area and Perimeter
This tutorial provides a brief introduction about what area is, then gives the formulas for area of a square, rectangle, parallelogram, trapezoid, triangle, and circle. Examples of each formula are provided.
Math Open Reference
Math Open Reference: Radius of a Circle
Learn about the radius of a circle with this useful reference guide. Provides a detailed definition, examples, and an interactive activity that enhances further explanation. Includes links to related topics.
Khan Academy
Khan Academy: Area and Parts of Circles
Practice finding the area or circumference of part of a circle. Students receive immediate feedback and have the opportunity to try questions repeatedly, watch a video or receive hints.
Khan Academy
Khan Academy: Circumference of a Circle
Practice finding the circumference of a circle.
Khan Academy
Khan Academy: Circumference of Parts of Circles
Practice finding circumference of parts of circles.
Khan Academy
Khan Academy: Area of Parts of Circles
Practice problems finding area of parts of circles.
Khan Academy
Khan Academy: Area and Circumference of Circles Challenge
Try these challenge problems involving area and circumference.
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...
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.
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.
PBS
Pbs Learning Media: Square Wheeled Tricycle: Radius and Circumference
This interactive exercise focuses on working with the radius of various circles to find the circumference and area as well as challenging you to find the distance a square wheel travels around the track.
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.
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.
Khan Academy
Khan Academy: Practice: Area of a Circle
A practice quiz on calculating the area of a circle. Includes hints.
Khan Academy
Khan Academy: Circumference and Rotations
Practice these problems with circumference and rotations.
Sophia Learning
Sophia: Finding a Formula for the Surface Area of a Cone
This video tutorial demonstrates how to find the formula for the surface area of a cone.