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 instructional activity, pupils understand how to find the radius,...
Curated OER
Area of Circles and Probability
Students investigate the area of squares and circles. In this geometry lesson, students calculate the area and probability of simple events. They work on a laptop using Safari.
Noyce Foundation
Circular Reasoning
Examine the origin and application of pi in five different levels. The five lessons in the resource begin with an analysis of the relationship between the radius and circumference of a circle. The following lessons lead learners through...
101 Questions
Coins in a Circle
Round and round you'll go! Learners watch as different-sized circles fill with coins. They collect data and then make a prediction about the number of coins that will fit in a large circular rug.
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.
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...
EngageNY
Unknown Length and Area Problems
What is an annulus? Pupils first learn about how to create an annulus, then consider how to find the area of such shapes. They then complete a problem set on arc length and areas of sectors.
EngageNY
What Is Area?
What if I can no longer justify area by counting squares? Lead a class discussion to find the area of a rectangular region with irrational side lengths. The class continues on with the idea of lower approximations and upper...
101 Questions
Circle-Square
How do the area and perimeters of circles and squares compare? A clever video illustrates the change in the area of a circle and square while their total perimeter stays the same. The task is for learners to predict the point where the...
Curated OER
Area of Circle Worksheets
In this geometry learning exercise, 10th graders calculate the area of circle give either the radius or the diameter. The one page interactive learning exercise contains ten questions. Answers and hints are included.
Curated OER
Circle Formulas
Tenth graders apply various circle formulas to determine radii, diameter, circumference, area, arc length, and sector area. The two page worksheet contains twenty-five problems. Answers are not provided.
EngageNY
Proving the Area of a Disk
Using a similar process from the first lesson in the series of finding area approximations, a measurement resource develops the proof of the area of a circle. The problem set contains a derivation of the proof of the circumference formula.
Mathematics Vision Project
Module 5: Circles A Geometric Perspective
Circles, circles, everywhere! Pupils learn all about circles, central angles, inscribed angles, circle theorems, arc length, area of sectors, and radian measure using a set of 12 lessons. They then discover volume formulas through...
EngageNY
Properties of Area
What properties does area possess? Solidify the area properties that pupils learned in previous years. Groups investigate the five properties using four problems, which then provide the basis for a class discussion.
West Contra Costa Unified School District
Finding the Equation of a Circle
Tired of going around and around for a resource on circles? Scholars determine the general equation of a circle on a coordinate plane, then participate in an activity matching equations to the radii and centers of the circles they...
Curated OER
Principles of Square Roots Lesson Plan
Middle and high schoolers investigate all the different places in math that square root is present. In this geometry lesson, pupils discuss square roots as it relates to a right triangle and construction. They go over altitude, rise,...
Curated OER
Lesson 9-3 Practice B: Composite Figures
In this composite figures worksheet, young scholars solve 11 short answer problems. Students find the area of figures composed of various polygons. Young scholars find the area of each figure given a sketch of the figure with various...
Curated OER
Circle Problems - Radius, Diameter, Circumference and Area
In this online math learning exercise, students determine the radius, circumference, diameter and area of circles. This excellent resource allows the students to check their answers, and to get "hints" should they run into difficulties....
Mathematics Assessment Project
Calculating Arcs and Areas of Sectors of Circles
Going around in circles trying to find a resource on sectors of circles? Here is an activity where pupils first complete an assessment task to determine the areas and perimeters of sectors of circles. They then participate in an activity...
Willow Tree
Area of Common Geometric Figures
Scholars can use area formulas, but can they apply what they know about area? The lesson plan challenges learners to think logically while practicing finding area of shapes such as rectangles, circles, parallelograms, triangles, and...
Mathematics Assessment Project
Solving Problems with Circles and Triangles
After completing a task involving examining the ratio of areas of triangles and circles in a given figure, scholars examine sample responses to identify other strategies they could use to solve the problem.
Mascil Project
Circular Pave-Stones Backyard
Pack the instructional activity into your plans. Young mathematicians learn about packing and optimization with the context of circular paving stones. They use coins to model the paving stones, and then apply knowledge of circles and...
Curated OER
Perimeter and Area
In this perimeter and area instructional activity, 9th graders solve 17 various types of problems, mostly word problems related to determining the area or perimeter of a geometric shape. They also determine the area and perimeter of...
101 Questions
Apple Mothership
Explore Apple's spaceship office building. Built in the shape of a circle, the office building offers a unique floor plan challenge. Young scholars use the dimensions of the building to estimate the square footage for each employee.