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...
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
Find Radius/Diameter
In this geometry worksheet, students calculate the radius and the diameter of the five given circles. There is an answer key included.
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. For this geometry lesson, 7th graders work in groups to find the diameter, radius, and circumference of circles....
Curated OER
Find Radius of the Circles
In this finding the radius of circles worksheet, students must calculate the radius of 4 circles. Students are given diameter and must write the radius on the line for each circle.
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.
Mathed Up!
Area and Circumference of Circles
Don't go around and around, help your class determine amounts around and in a circle with a video that connects circumference to the perimeter or the distance around an object. The resource includes 14 questions dealing with circles and...
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...
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
Arc Length and Areas of Sectors
How do you find arc lengths and areas of sectors of circles? Young mathematicians investigate the relationship between the radius, central angle, and length of intercepted arc. They then learn how to determine the area of sectors of...
Curated OER
An Introduction to Pi and the Area of a Circle
Students explore measurements of a circle. In this instructional activity about circumference and radius, students practice calculating measurements of a circle. Students estimate, calculate, and practice with graphing all while...
Curated OER
Math and Circumference
Sixth graders explore geometry by utilizing mathematical formulas. In this circumference lesson plan, 6th graders identify the difference between diameter, circumference and radius in a circle. Students review the formulas for finding...
Curated OER
Don't Be a Square
Students analyze the relationship between radius and diameter. Students read Sir Cumference and the First Round Table then take measurements of circular items from around the room. Students compute the radius, diameter...
Curated OER
Circle Circus
Third graders find the radius and diameter of a bubble. In this radius and diameter lesson, 3rd graders create bubbles on their desk and find the radius and diameter of the bubble. Students work in partners to define circle terms and...
Curated OER
Circles
In this circles worksheet, 10th graders solve and complete 20 different problems related to various circles. First, they find the radius and diameter of a circle with a given circumference. Then, students determine the measure of each...
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
Volume of Cylinders and Cones
Line drawings of a circle, a cylinder, and a cone at the top of the page contain the formulae for area and volume of each shape. Learners complete the missing information in a chart that lists diameter, radius, height, and area and...
Curated OER
Finding the Circumference and Area of a Circle
Sixth graders discover what circumference is. In this measurement lesson, 6th graders identify the radius and diameter of different circles. Students discover how to find the area of a circle using the radius and diameter.
Curated OER
Circles and Pi
Young scholars identify the relationship between the radius and Pi. In this geometry lesson plan, students calculate the circumference and area of a circle. They create visuals to help them see how the circumference relates to Pi.
Curated OER
Discovering Pi
Sixth graders measure circumference and diameter to the nearest eighth of an inch, record measurements on a spreadsheet, and use the internet to complete a "scavenger hunt" of facts concerning pi.
EduGAINs
Discovery of Pi
Serve up a slice of math for Pi Day! A combination of fun, hands-on lessons and helpful worksheets encourage learners to practice finding the radius, diameter, and circumference of different circles.
Virginia Department of Education
Arc Length and Area of a Sector
What do skateboarding and baked goods have in common with math? You can use them to connect half-pipe ramps and cakes to arcs and sectors. Pupils compare the lengths of three different ramp options of a skate park. They calculate the...
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...