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: 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.
Shmoop University
Shmoop: Basic Geometry: Area (Polygon, Triangle, Circle, Square)
The geometry resource investigates the area of polygons, triangles, circles, and squares. Formulas and examples are included.
Oswego City School District
Regents Exam Prep Center: Circles, Segments, and Area
A wealth of resources to supplement instruction on parts of the circle. Find lessons describing chords, tangents, secants, and segments, as well as related practice quizzes and classroom activities.
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...
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.
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...
Khan Academy
Khan Academy: Area and Circumference of Circles Challenge
Try these challenge problems involving area and circumference.
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...
Shmoop University
Shmoop: Basic Geometry: Area Formulas
The geometry resource investigates the area of polygons, triangles, circles, and squares. Formulas, examples, and practice exercises are included.
Maths Challenge
Maths challenge.net: Rectangular Circles
An area problem involving finding the area of a rectangle and a circle. The problem may be made into a general proof as well.
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.
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.
CK-12 Foundation
Ck 12: Examining Circles: Area of a Circle
[Free Registration/Login Required] Students use the radius and diameter to determine the area of a circle. Click challenge me to answer practice questions and click learn more to watch a video.
CK-12 Foundation
Ck 12: Area of a Circle: Hula Hoop Radius
[Free Registration/Login Required] Students use the radius and diameter to determine the area of a circle. Click challenge me to answer practice questions and click learn more to watch a video.
CK-12 Foundation
Ck 12: Area of a Circle: Campsite
[Free Registration/Login Required] Students are given the radius and diameter to solve for the area of a circle. Click challenge me for practice problems and click learn more to watch a video.
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.
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.
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 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.
Analyze Math
Analyze Math: Sectors and Circles Problems
Try these three problems regarding area of sectors, length of arcs, and central angles. The problems will challenge and intrigue sharp geometry students. Detailed written solutions are included.
Maths Challenge
Maths challenge.net: Lunes
A "three star" geometry problem where some experience of math problem solving skills and knowledge of circles is recommended to solve this lunes (parts of a circles) area problem
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 the area of the circle
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.