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 then provides an exercise set for learners to...
Curated OER
Congruent Segments
The task, should your class decide to take it, is to list a series of reflections that transfer a line segment from one position to another.
EngageNY
Similar Triangles in Circle-Secant (or Circle-Secant-Tangent) Diagrams
First angle measures, now segment lengths. High schoolers first measure segments formed by secants that intersect interior to a circle, secants that intersect exterior to a circle, and a secant and a tangent that intersect exterior to a...
Curated OER
Connecting Algebra and Geometry Through Coordinates
This unit on connecting algebra and geometry covers a number of topics including worksheets on the distance formula, finding the perimeter and area of polynomials, the slope formula, parallel and perpendicular lines, parallelograms,...
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...
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...
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 and...
Inside Mathematics
Circles in Triangles
Challenge the class with inscribed circles in triangles. The assessment task requests class members use their knowledge of circles and right triangles to prove two triangles are congruent. They go on to utilize their knowledge of...
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...
Illustrative Mathematics
The Geometry of Letters
Use the alphabet as a tool for teaching your class about geometric figures. Break apart capital letters into line segments and arcs. Classify angles as right, acute, or obtuse. Identify parallel and perpendicular lines. An excellent...
EngageNY
Tangent Segments
What's so special about tangents? Learners first explore how if a circle is tangent to both rays of an angle, then its center is on the angle bisector. They then complete a set of exercises designed to explore further properties and...
EngageNY
Circles, Chords, Diameters, and Their Relationships
A diameter is the longest chord possible, but that's not the only relationship between chords and diameters! Young geometry pupils construct perpendicular bisectors of chords to develop a conjecture about the relationships between chords...
EngageNY
Equations for Tangent Lines to Circles
Don't go off on a tangent while writing equations of tangent lines! Scholars determine the equations for tangent lines to circles. They attempt both concrete and abstract examples, such as a tangent line to the unit circle through (p, 0).
EngageNY
Construct a Square and a Nine-Point Circle
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...
Curated OER
Finding Circumference and Area of a Circle
Young geometers explore the concept of circumference and area of circles. They discuss what information is needed to find circumference and area. The resource employs several instructional methods: Frayer Model for Vocabulary, literature...
Dick Blick Art Materials
Start with a Circle...
The Golden Ratio. The Divine Proportion. Yup. It's math and art blended into one colorful activity. Young artists combine colored tissue paper circles and parts of circles to create geometric patterns. As a bonus, kids get to figure out...
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.
Curated OER
Inscribing a Square in a Circle
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...
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 information about...
Virginia Department of Education
Angles, Arcs, and Segments in Circles
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...
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
Stained Glass
A complex question looking for the total cost of a stained glass window by calculating area and circumference of a circle. With detailed components, this activity will challenge your designers to figure out if they have enough money to...
Curated OER
Midpoint of a Line Segment
In this line segment instructional activity, 10th graders identify and solve 10 different problems that include determining the midpoint of a line segment in each. First, they determine the midpoint of a segment that connects two points....
Curated OER
Angles in Circles
In this angles in circles worksheet, 10th graders solve 10 different problems that include tangents and chords and intersecting chords. First, they find x when given 2 intersecting chords. Then, students determine x given the diameter...