Math Open Reference
Math Open Reference: Circles
A complete reference guide to circles including parts, angles, and arcs. It provides definitions and interactive activities that enhance further explanation.
Illustrative Mathematics
Illustrative Mathematics: G Srt, G Mg Coins in a Circular Pattern
For this task, students investigate how many coins will fit around a central coin when they are all of the same denomination, and if there is room left over. The teacher is given a chart of four coin denominations and their diameters,...
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.
CK-12 Foundation
Ck 12: Statistics: Circle Graphs to Display Data Grades 6 7
[Free Registration/Login may be required to access all resource tools.] Here you'll display data by using a circle graph.
Mocomi & Anibrain Digital Technologies
Mocomi: What Is Circle?
Discusses the radius, diameter, circumference, and area of a circle.
Texas Instruments
Texas Instruments: Circle Around
In this activity, students compute the circumference and area of circles. They understand that the ratio of the circumference to the diameter is a value called pi. [Requires Adobe Reader.]
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.
Other
Simple Science: Slice of Pi
The interactive tutorial explores the history behind Pi and how to find its value. Students use images of circular objects and find the diameter and circumference to obtain an approximate value of Pi. The resource has an interactive...
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.
Science and Mathematics Initiative for Learning Enhancement (SMILE)
Smile: Diameter,circumference,radius & the Discovery of Pi
This site provides a good project for students to use to explore the circumference of a circle.
Texas Instruments
Texas Instruments: Predicting Pi
In this activity, students explore the use of linear measurement and calculators to discover the existence of pi, the constant ratio between the circumference and the diameter of a circle.
TOPS Learning Systems
Top Science: Pi Graph [Pdf]
An activity where students explore and graph the relationship between the diameter and the circumference of a circle.
CK-12 Foundation
Ck 12: Geometry: Circumference
[Free Registration/Login may be required to access all resource tools.] This concept teaches students how to calculate the circumference of a circle. Students examine guided notes, review guided practice, watch instructional videos and...
Government of Alberta
Learn Alberta: Exploring the Diameter and Circumference
This multimedia site offers a beginner's guide to understanding the relationship between the diameter and circumference of a circle. This Learn Alberta site offers a video [1:44], interactive exercises and printable extended exercises.
PBS
Pbs Learning Media: Math + Arts: Circle Designs
In this lesson, students explore circumference and diameter by creating an abstract design with circles. Media resources and teacher materials are included.
Math Open Reference
Math Open Reference: Diameter
A complete reference guide to diameters. It provides definitions, examples, and interactive activities that enhance further explanation. Includes links to related topics.
Illustrative Mathematics
Illustrative Mathematics: G Srt, G Mg Seven Circles Iii
In this task, young scholars are shown circle formations where an inner circle is surrounded by a set of circles and all circles are touching. In the first situation, all circles have the same diameter. In the second, the inner circle is...
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.
Illustrative Mathematics
Illustrative Mathematics: G Gpe.5 Triangles Inscribed in Circle
In this task, students use ideas about linear functions to determine when certain angles are right angles. They use the fact that two lines (if not vertical or horizontal) are perpendicular when their slopes are inverse reciprocals, as...
Illustrative Mathematics
Illustrative Mathematics: G C Right Triangles Inscribed in Circles I
This task provides a good opportunity to use isosceles triangles and their properties to show an interesting and important result about triangles inscribed in a circle with one side of the triangle a diameter. The fact that these...
CK-12 Foundation
Ck 12: Interactive Geometry: 8.2 Area and Circumference of Circles
A deep dive into the area and circumference of circles.
Illustrative Mathematics
Illustrative Mathematics: G C Right Triangles Inscribed in Circles Ii
In this task, learners analyze the characteristics of a right triangle that has two sides labeled with midpoints and show that the triangle is inscribed in a circle with a diameter the length of its hypotenuse. Aligns with G-C.A.2.
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.
Illustrative Mathematics
Illustrative Mathematics: G Gpe Slopes and Circles
The purpose of this task is to lead young scholars through an algebraic approach to a well-known result from classical geometry, namely, that a point X is on the circle of diameter AB whenever angle AXB is a right angle. This consists of...