+
Lesson Plan
EngageNY

Rectangles Inscribed in Circles

For Teachers 9th - 10th Standards
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...
+
Lesson Plan
EngageNY

Construct a Square and a Nine-Point Circle

For Students 9th - 10th Standards
Anyone can draw a square, but can you CONSTRUCT a square? Here is a resource that challenges math scholars to create steps to finish their own construction. They test their ability to read and follow directions to complete a construction...
+
Assessment
EngageNY

Geometry Module 5: Mid-Module Assessment

For Teachers 9th - 12th Standards
How can you formally assess understanding of circle concepts? Pupils take a mid-module assessment containing five questions, each with multiple parts.
+
Lesson Plan
Curated OER

Geometry: Area, Scale Factor, Circumference

For Teachers 5th - 8th
In this geometry worksheet, students solve 10 problems regarding area, scale factors, and circumference. Students, in 3 of the problems, are given the circumference and asked to work backwards to find missing information.
+
Worksheet
Curated OER

Circumference and Area of Circles (B)

For Students 5th - 6th
In this geometry activity, students calculate the area and circumference of 12 circles in which either the diameter or radius is shown. There are no formulas given on this page.
+
Lesson Plan
Curated OER

Equations of Circles

For Teachers 9th - 12th Standards
Using Cabri Jr. students construct a circle and determine the equation of the circle they drew by finding the center and the radius. Students use the distance formula to derive the equation of their circle.
+
Lesson Plan
EngageNY

Properties of Tangents

For Teachers 9th - 12th Standards
You know about the tangent function, but what are tangent lines to a circle? Learners investigate properties of tangents through constructions. They determine that tangents are perpendicular to the radius at the point of tangency, and...
+
Lesson Plan
Curated OER

Tangent Lines and the Radius of a Circle

For Teachers 9th - 12th Standards
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. 
+
Activity
Curated OER

Inscribing a Square in a Circle

For Teachers 9th - 11th Standards
Inscribing a square in a circle brings up a number of interesting geometry topics including triangle congruence and how to prove a quadrilateral is a square. This activity is followed up by finding the area of the square and determining...
+
Interactive
CK-12 Foundation

Equations of Circles: The Sea of Happiness

For Students 11th - Higher Ed Standards
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...
+
Assessment
Mathematics Assessment Project

Temple Geometry

For Students 8th - 10th Standards
Temper your excitement of temple geometry. Using algebraic and geometry concepts to determine various measurements in a circle diagram, scholars determine the shaded area of the diagram.
+
Lesson Plan
Virginia Department of Education

Angles, Arcs, and Segments in Circles

For Teachers 9th - 11th Standards
Investigate relationships between angles, arcs, and segments in circles. Pupils use geometry software to discover the relationships between angles, arcs, and segments associated with circles. Class members use similar triangles to...
+
Unit Plan
Mathematics Vision Project

Module 6: Connecting Algebra and Geometry

For Teachers 9th - 12th Standards
A geometry module connects algebraic reasoning to geometry. It challenges scholars to investigate the slope criteria for parallel and perpendicular lines, prove theorems involving coordinate geometry, and write equations for circles and...
+
Assessment
Mathematics Assessment Project

Geometry

For Students 7th - 8th Standards
Help learners find joy in facing mathematical challenges. The questions posed on this worksheet encourage young mathematicians to utilize skills learned throughout a geometry unit, and to apply themselves and persevere through problem...
+
Worksheet
Curated OER

Geometry Review

For Students 10th
In this geometry review worksheet, 10th graders solve and complete 33 different problems that include identifying various geometric figures and parts of a circle. First, they find the radius of each circle given its diameter. Then,...
+
Lesson Plan
Curated OER

Chords of a Circle

For Teachers 10th
In this geometry worksheet, 10th graders calculate the length of a chord and the distance from the center of a circle or radius. They compare diameter, chords and radius. There are 10 questions with an answer key.
+
Worksheet
Curated OER

Skills Practice: Area of Circles

For Students 7th - 8th
Two practice pages with 10 problems each show circles and give their radii. Learners calculate the area. Answers are provided. 
+
Lesson Plan
Curated OER

Discovering Pi/Welcome to Pi Day

For Teachers 9th - 12th
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...
+
Lesson Plan
Curated OER

Angles, Triangles, Quadrilaterals, Circles and Related

For Teachers 6th - 8th
Students classify angles. In this angles lesson, students explore the characteristics of angles, triangles, quadrilaterals and circles. They identify polygons and sing a classifying angles song. Students participate in a manipulative...
+
Lesson Plan
EduGAINs

Discovery of Pi

For Teachers 8th Standards
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.
+
Lesson Plan
Illustrative Mathematics

Two Wheels and a Belt

For Teachers 9th - 10th Standards
Geometry gets an engineering treatment in an exercise involving a belt wrapped around two wheels of different dimensions. Along with the wheels, this belt problem connects concepts of right triangles, tangent lines, arc length, and...
+
Worksheet
Curated OER

Making a Six-pointed Star

For Students 7th - 8th
In this polygon worksheet, students identify and create a six-pointed star by completing 6 steps. First, they use a compass to trace a circle with a given radius. Then, students draw a point on circumference of the circle and place the...
+
Worksheet
Curated OER

Geometry: Calculating the Area of a Circle

For Students 7th - 9th
In this area worksheet, students use the perimeter or radius to determine the area of a circle. This one-page worksheet contains 8 problems. This worksheet may be produced in printed form. Answers may be viewed on-line.
+
Worksheet
Curated OER

Circles

For Students 3rd - 4th
In this circles worksheet, students fill in 6 fill in the blank statements about circles and solve calculate the answers to 13 questions involving different measurements of circles.