Curated OER
Tangent Lines and the Radius of a Circle
Your Geometry learners will collaboratively prove that the tangent line of a circle is perpendicular to the radius of the circle. A deliberately sparse introduction allows for a variety of approaches to find a solution.
EngageNY
Writing the Equation for a Circle
Circles aren't functions, so how is it possible to write the equation for a circle? Pupils first develop the equation of a circle through application of the Pythagorean Theorem. The lesson plan then provides an exercise set for learners...
Curated OER
The Circumference of a Circle and the Area of the Region it Encloses
Bring your math class around with this task. Learners simply identify parts of a given circle, compute its radius, and estimate the circumference and area. It is a strong scaffolding exercise in preparation for applying the formulas for...
CK-12 Foundation
Equations of Circles: Finding the Equation of a Circle
It's all about location and size. With the aid of the interactive, pupils explore the relationship between the location and size of a circle and its equation. The learners use that relationship to determine the equation of a circle given...
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...
Curated OER
Explaining the equation for a circle
By first starting with an explicit example of a radius and center point, this challenging lesson tries to help high schoolers gain an understanding of the Pythagorean theorem and the equation of a circle. Once they have accomplished the...
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...
Curated OER
Area of a Circle When Radius is Given
Five problems provide practice for learners to find the area of a circle given the distance of the radius. Answers on the key use pi as a variable and do not include fully computed numeric answers. To reinforce basic multiplication facts...
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
Eight Circles
We are used to finding the area of a circle by plugging the radius into an equation. Here, learners are required to go further to find multiple areas and calculate the difference. They must detect a pattern in order to figure out the...
Virginia Department of Education
Circles in the Coordinate Plane
Make the connection between the distance formula and the equation of a circle. The teacher presents a lesson on how to use the distance formula to derive the equation of the circle. Pupils transform circles on the coordinate plane and...
Corbett Maths
Hexagon Inscribed Within a Circle
Mark off the length of the radius around the circle. Using a compass, the presenter shows how to construct a regular hexagon in a circle. Pupils see how triangles formed in the hexagon are equilateral, allowing for the construction to...
Curated OER
Quiz: Area of a Circle
Geometers test their mastery at finding the area of a circle with 10 basic problems. Circle diagrams show line segments, points, and diameter. Distance of radii are given. They use pi as 3.14 to calculate the area. No answer key is...
Curated OER
The Area of a Circle
Eighth graders find the circumference and diameter of several lids, show the relationship of the two measurements and derive the formula for finding the area of a circle. In this area of a circle lesson plan, 8th graders find...
EngageNY
Proving the Area of a Disk
Using a similar process from the first lesson plan 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...
Curated OER
Length of a Line Segment - Distance
Pupils determine the distance between two given points. They use the distance formula to determine line length, as well as the length of the radius of a circle. The Pythagorean Theorem may also be used to determine line length. This...
Curated OER
Circumcenter of a Triangle
Your geometry learners will discover and show the construction of the circumcenter of a triangle. Guided by the steps in the activity, they construct perpendicular bisectors of each side that have a point of concurrency called the...
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...
Texas Instruments
Drawing a Line Tangent to a Circle
Explore lines tangent to a circle. In this math lesson, students manipulate circles and lines on a TI calculator. They draw a circle and analyze perpendicular lines intersecting the circle in only one place. This activity works...
Curated OER
Area Of A Circle
Students 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...
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...
CK-12 Foundation
Circles Centered at the Origin: The Map of the Beta Solar System
Calculate galactic orbits in a far-out resource. Pupils drag a point on a circle to graph the orbit of a fictional planet. Using the equation, they find points through which the orbit passes. To finish the simulation, users determine the...
CK-12 Foundation
Equations of Circles: The Sea of Happiness
Map this! Help your young mathematicians draw a circular island on a map. Given specifics of the location and size of an island on a map, pupils transform a circle to meet the given requirements. They then determine the location of the...
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...