Khan Academy
Khan Academy: Circumference and Rotations
Practice these problems with circumference and rotations.
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.
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.
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.]
Common Core Sheets
Common Core Sheets: Geometry 7.g.4 Worksheets: Area and Circumference Circle
Worksheets provide practice with finding the area or circumference of a circle and answer keys are provided. You can even create your own instructional activity or flashcards.
Illustrative Mathematics
Illustrative Mathematics: G Gmd Area of a Circle
For this task, learners 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.
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.
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.
Alabama Learning Exchange
Alex: Arc Lengths and Sector Areas
Students 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 area....
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...
Other
Visnos: Explore Pi
This interactive demonstration shows firstly how pi relates to the circumference of a circle. This is achieved using a regular polygon approximation, the closed polygon is opened to reveal this magical number. The area of a circle is...
ClassFlow
Class Flow: Circles
[Free Registration/Login Required] This flipchart has information and practice regarding finding area and circumference of circles.
ClassFlow
Class Flow: Circles and Angles
[Free Registration/Login Required] In this flipchart students practice identifying parts of a circle, measure angles, and practice solving area and circumference problems.
Ministry of Education and Universities of the Region of Murcia (Spain)
Ministerio De Educacion Y Ciencia: Circunferencia Y Circulo: Longitudes Y Areas
Reinforce your knowledge of the circumference and the area of a circle with these activities. [Requires Java.]
Learning Wave Communications
Learning Wave: Geometry, Section 2
Geometry concepts are briefly discussed at this site, including volume of a cylinder, parallelograms, circles, trapezoids, and triangles. Sample problems and applications are included for practice.
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.
Texas A&M University
Wtamu Virtual Math Lab: Beginning Algebra: Formulas
This tutorial will show you how using formulas can help you solve problems. Include formulas for various geometric shapes and steps showing how to use them.
Alabama Learning Exchange
Alex: Circling Around
Learners will calculate the diameter, circumference, and ratio of a real world object. Students will create an electronic slideshow to illustrate the process of determining the diameter, circumference, and ratio of these objects.