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.]
Analyze Math
Analyze Math: Overlapping Circles Problem
Try this problem - find the area of the overlapping region of two overlapping circles. You need to find the region of each segment, then add them up. This site gives the problem and a detailed written solution. Good problem for sharp...
Khan Academy
Khan Academy: Problem Solving With Area and Circumference of Circles
In this exercise, students practice problem solving the area and circumference of circles. Students receive immediate feedback and have the opportunity to get hints and try questions repeatedly.
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.
CK-12 Foundation
Ck 12: Area of Composite Shapes
[Free Registration/Login Required] Students explore how to break down shapes to determine the area of a figure. Click challenge me to answer practice questions and click learn more to watch a video.
University of St. Andrews (UK)
University of St. Andrews: James Gregory
This site, which is provided for by the University of St. Andrews, contains information on the mathematician Gregory and his accomplishments.
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.
CK-12 Foundation
Ck 12: Area of Sectors and Segments: Pacman Area
[Free Registration/Login Required] Students are to determine the area of the shaded region between two radii. Click challenge me to answer practice questions and click learn more to watch a video.
Government of Alberta
Learn Alberta: Math Interactives: Exploring Surface Area, Volume, and Nets
Investigate the concepts of area, volume, 3D shapes, and nets using this interactive Learn Alberta math. The solid shapes focused on this exploration include rectangular and triangular prisms, rectangular and triangular pyramids,...
Calculator Soup
Calculator Soup: Surface Area Calculator
Online calculator to calculate the surface area of geometric solids including a capsule, cone, frustum, cube, cylinder, hemisphere, pyramid, rectangular prism, sphere, spherical cap, and triangular prism
CK-12 Foundation
Ck 12: Interactive Geometry: 8.10 Sector Area
Learn and understand the sector of a circle.
Math Is Fun
Math Is Fun: Circle Sector and Segment
Learn about the "two main 'slices' of a circle" called a sector and a segment, and see how you can calculate the area of a sector or segment using trigonometry.
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.
Khan Academy
Khan Academy: Shaded Areas
Find the areas of shaded regions which are combinations of squares, triangles, and circles. Students receive immediate feedback and have the opportunity to try questions repeatedly, watch a video or receive hints.
Common Core Sheets
Common Core Sheets: Geometry 8.g.3 Worksheets: Coordinate Plane
Worksheets provide practice with finding the area or circumference of a circle and answer keys are provided. You can even create your own worksheet or flashcards.
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.
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.
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.
Math Planet
Math Planet: Geometry: Parallelogram, Triangles Etc
Resource examines the area of geometric solids through examples and a video lesson. [0:39]
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.
Analyze Math
Analyze Math: Polygons Problems
Here are four problems about the area of a regular polygon. Start by finding the area of a hexagon inscribed in a circle of radius 10, and end by proving that as the number of sides of the polygon increases, the area of the polygon...
Cuemath
Cuemath: Cylinder
Mini-lesson takes a look at the definition and shape of a cylinder, cylinder formula, cylinder volume, and cylinder surface area. Try your hand at the cylinder surface area calculator and interactive questions for better understanding.
Other
Allmath: Math Glossary
Are your students having difficulty understanding math terminology? Try this A-Z glossary on math related terms. It's quick, easy to read, and very complete.
PBS
Pbs Mathline: Bubble Mania Lesson Plan [Pdf]
Determine the area, diameter, and circumerfence of a bubble residue by creating a soap solution and blowing bubbles.