Curated OER
Circumferences, Diameters, and Radii
Learners explore circumferences, diameters, and radii. In this math lesson plan, students measure circumferences in inches and compute radii and diameters, given different circumferences.
Illustrative Mathematics
Coins in a Circular Pattern
What starts as a basic question of division and remainders quickly turns abstract in this question of related ratios and radii. The class works to surround a central coin with coins of the same and different values, then develops a...
Curated OER
Measuring the Area of a Circle
When mathematical errors happen, part of the learning is to figure out how it affects the rest of your calculations. The activity has your mathematicians solving for the area of a circular pipe and taking into consideration any errors...
National Research Center for Career and Technical Education
Transportation, Distribution, and Logistics: Tire and Wheel Assemblies
Is bigger really better? By the end of this lesson, learners will be able to apply formulas for computing the diameter of tires and wheel assemblies. Begin by showing a slide presentation that will review definitions for radius and...
Curated OER
Circles-Diameter, Circumference, Radius and the Discovery of Pi
Seventh graders measure the diameter, circumference and radius of a circle and find pi using the diameter and circumference. In this geometry lesson, 7th graders work in groups to find the diameter, radius, and circumference of circles....
Mt. San Antonio Collage
Circles
Don't circle around the topic, but get right to the center with tons of practice regarding circles in geometry. The note-incorporated worksheet provides guided practice through many topics such as central angles, inscribed polygons...
Curated OER
Circle Circus
Third graders find the radius and diameter of a bubble. In this radius and diameter instructional activity, 3rd graders create bubbles on their desk and find the radius and diameter of the bubble. Students work in partners to define...
Curated OER
Discovering Pi/Welcome to Pi Day
Students explore pi. In this circle measurement lesson, students define and identify radius, diameter, circumference, and perimeter. Students work in groups to measure several plastic lids and record their findings. Students compare the...
Illustrative Mathematics
Right Triangles Inscribed in Circles II
So many times the characteristics of triangles are presented as a vocabulary-type of lesson, but in this activity they are key to unraveling a proof. A unique attack on proving that an inscribed angle that subtends a diameter must be a...
Curated OER
Exploring Diameter and Circumference
Learn how to identify the diameter and circumference of a circle. Then, collect data on a circle and relate it to the diameter and circumference of a circle. Last, plot data and find the line of best fit.
Curated OER
Space Circles
Fifth graders calculate the diameters and radius of planets as a book is read to them. In this diameter and radius lesson plan, 5th graders read the book Space Circles and calculate the measurements based on the information in this book.
Mathematics Vision Project
Circles: A Geometric Perspective
Circles are the foundation of many geometric concepts and extensions - a point that is thoroughly driven home in this extensive unit. Fundamental properties of circles are investigated (including sector area, angle measure, and...
Mathematics Assessment Project
Inscribing and Circumscribing Right Triangles
High schoolers attempt an assessment task requiring them to find the radii of inscribed and circumscribed circles of a right triangle with given dimensions. They then evaluate provided sample responses to consider how to improve...
EngageNY
The Area of a Circle
Introduce learners to two methods to estimate the formula for the area of a circle. The first method uses a sector of a circle to form a rectangle, and the other uses grids to estimate the area. The problems in the 18th segment of a...
Illustrative Mathematics
Tangent to a Circle From a Point
Learners see application of construction techniques in a short but sophisticated problem. Combining the properties of inscribed triangles with tangent lines and radii makes a nice bridge between units, a way of using...
Curated OER
Circles and Cylinders
In this geometry lesson, 10th graders break down a circle and identify the different parts. They discuss chords, diameter, radius, circumference, major and minor segment. There are 42 problems broken down into 5 different sections.
Illustrative Mathematics
Seven Circles III
A basic set-up leads to a surprisingly complex analysis in this variation on the question of surrounding a central circle with a ring of touching circles. Useful for putting trigonometric functions in a physical context, as well as...
Flipped Math
Circles and Arc Lengths
Discuss all things round and round. Pupils review finding area and the circumference of circles and use them to solve problems. Next, they learn about central angles and their relationships to measures of arcs. Learners then find out how...
Texas Instruments
Area of Circles
Students explore circles. In this algebra/geometry lesson, students discover the formula for the area of a circle, as they investigate the ratio of the area of a circle to the radius^2.
Curated OER
Algebra II - Lesson 10-3: Circles
In this equations of circles instructional activity, high schoolers solve 4 short answer problems. Students find an equation of a circle given the center and radius.
Illuminations
Circumference and Areas of Circles
Middle and high schoolers listen to a scenario about a puppy and use the scenario to develop formulas in order to find the area of a circle. In this circumference lesson, pupils understand how to find the radius, diameter, area of a...
Curated OER
Area Of A Circle
Learners investigate the concept of area and how it can be applied to a circle. They use the right formula in order to solve different problems. The teacher leads the class through different examples and serves as a resource during...
EngageNY
Rectangles Inscribed in Circles
Putting a rectangular object into a circular one—didn't the astronauts on Apollo 13 have to do something like this? Learners first construct the center of a circle using perpendiculars. They then discover how to inscribe a rectangle in a...
EngageNY
Arcs and Chords
You've investigated relationships between chords, radii, and diameters—now it's time for arcs. Learners investigate relationships between arcs and chords. Learners then prove that congruent chords have congruent arcs, congruent arcs have...