Purple Math
Purplemath: Sectors, Areas, and Arcs
Explains formulas for areas of sectors of circles and lengths of arcs. Demonstrates how to use the formulas in each of degrees and radians.
Purple Math
Purplemath: The Unit Circle
Relates the unit circle to the method for finding trig ratios in any of the four quadrants. Demonstrates how the unit circle might be useful.
Sophia Learning
Sophia: Determining Unknown Values Using the Volume of a Cylinder
This video lesson demonstrates how to work backward and use the volume of a cylinder to find an unknown value such as the radius or height. Students can check their understanding with an assessment. [4:41]
ClassFlow
Class Flow: Circle Vocabulary
[Free Registration/Login Required] This lesson lets students identify, draw, and measure parts of a circle. The lesson compliments 5th grade Harcourt Math, Lesson 23.4. Activote assessment is included at the end of the lesson.
Rice University
Rice University: Cynthia Lanius: Circles Around Pythagoras
This site from the Rice University includes a fill-in-the-blank lesson on the definition of circles, as Pythagoras described.
Homeschool Math
Homeschool Math: Circles
Lesson presents definitions of terms associated with circles and helps young scholars learn to use a compass to draw circles and simple circle designs.
CK-12 Foundation
Ck 12: Geometry: Area of a Circle
[Free Registration/Login may be required to access all resource tools.] In this lesson students find the area of a circle given its radius or diameter. Students examine guided notes, review guided practice, watch instructional videos and...
NASA
Nasa: Imagine the Universe: How Big Is That Star
This 2-5 day lesson plan investigates the diameter, radius and mass among several stars in order to understand stellar behavior, particularly in a binary system.
TeachEngineering
Teach Engineering: Ring Around the Rosie
Young scholars learn the concept of angular momentum and its correlation to mass, velocity and radius. They experiment with rotation and an object's mass distribution. In an associated literacy activity, students use basic methods of...
CK-12 Foundation
Ck 12: Geometry: Segments From Chords
[Free Registration/Login may be required to access all resource tools.] Looks at how to apply the Intersecting Chords Theorem.
CK-12 Foundation
Ck 12: Geometry: Parts of Circles
[Free Registration/Login may be required to access all resource tools.] This concept teaches students the vocabulary for the parts of circles, including lines passing through circles.
CK-12 Foundation
Ck 12: Geometry: Surface Area and Volume of Cones
[Free Registration/Login may be required to access all resource tools.] This concept teaches students to calculate the surface area and volume of a cone.
CK-12 Foundation
Ck 12: Geometry: Chords in Circles
[Free Registration/Login may be required to access all resource tools.] This concept teaches students four theorems about chords and how to apply them. Students examine guided notes, review guided practice, watch instructional videos and...
CK-12 Foundation
Ck 12: Geometry: Area of a Circle
[Free Registration/Login may be required to access all resource tools.] This concept teaches students how to calculate the area of a circle. Students examine guided notes, review guided practice, watch instructional videos and attempt...
CK-12 Foundation
Ck 12: Geometry: Circles in the Coordinate Plane
[Free Registration/Login may be required to access all resource tools.] This concept teaches students how to graph circles and find the standard equations of circles. Students examine guided notes, review guided practice, watch...
Mathigon
Mathigon: Geometry: Euclidean Geometry: Definitions
This lesson focuses on Euclidean Geometry terminology; such as line, point, line segment, congruence, circle, radius, ray, and more. It defines each term and provides an example of each.
CK-12 Foundation
Ck 12: Interactive Geometry: 1.8 Circles
Understand circles and their measurement applications.
Quia
Ixl Learning: Circumference of Circles
Brush up on your math skills relating to the circumference of circles of measurement then try some practice problems to test your understanding.
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.
National Council of Teachers of Mathematics
The Math Forum: Pi Day
Need some ideas for Pi Day on March 14th? You can get some great resources at this location. There are all kinds of links available.
Purple Math
Purplemath: Quadrants and Angles
Explains how to model angles in the x,y-plane, and demonstrates how to extend the concept of trig ratios to angles larger than 90 degrees.
CK-12 Foundation
Ck 12: Geometry: Pi
[Free Registration/Login may be required to access all resource tools.] Identify pi as the ratio of a circle's diameter to a circle's circumference.