Curated OER
Inscribed Angles and Arcs
In this inscribed angles and arcs worksheet, 10th graders solve and complete 21 various types of problems. First, they find the measure of each inscribed angle. Then, students find the measure of each angle or arc in a circle with the...
EngageNY
Secant Lines; Secant Lines That Meet Inside a Circle
Young mathematicians identify different cases of intersecting secant lines. They then investigate the case where secant lines meet inside a circle.
EngageNY
Secant Angle Theorem, Exterior Case
It doesn't matter whether secant lines intersect inside or outside the circle, right? Scholars extend concepts from the previous lesson to investigate angles created by secant lines that intersect at a point exterior to the circle....
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...
Curated OER
Triangles Inscribed in a Circle
Are you tired of answers without understanding? Learners can give a correct response, but do they really understand the concept? Have young mathematicians think deeper about linear functions, angles, and formulas in algebra....
Flipped Math
Intercepted Arcs
Intercept the class's learning on circles. Pupils learn the relationship between intercepted arcs and inscribed angles. The scholars use that information to find the relationship of angles in an inscribed quadrilateral and an angle...
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...
Mathed Up!
Circle Theorems
Explore theorems involving circles. Individuals watch a video that reviews the basic parts of a circle. They learn about circle theorems and compete a worksheet of problems that use these theorems — putting their skills to work right away!
Radford University
Where Should We Sit?
Where's the best seat in the house? Given a diagram of a movie theater, pupils determine the best seats based on the viewing angle. They use inscribed angles to justify their choices.
EngageNY
Ptolemy's Theorem
Everyone's heard of Pythagoras, but who's Ptolemy? Learners test Ptolemy's Theorem using a specific cyclic quadrilateral and a ruler in the 22nd installment of a 23-part module. They then work through a proof of the theorem.
EngageNY
Geometry Module 5: Mid-Module Assessment
How can you formally assess understanding of circle concepts? Pupils take a mid-module assessment containing five questions, each with multiple parts.
Curated OER
Inscribed Angles
Students analyze inscribed angles and intercepted arcs and explore the relationships between the two. They investigate the properties of angles, arcs, chords, tangents, and secants to solve problems involving circles.
Curated OER
Properties of Arcs, Lengths and Chords
Young scholars differentiate between the different properties of arcs, arc lengths, chords, and chord lengths. In this circles lesson, students calculate the arc length of a given circle, and find the measure of the inscribed angles of a...
Curated OER
Inscribed and Central Angles in a Circle
In this geometry worksheet, students find the missing angle that is inscribed inside of a circle. They define vocabularies related to the circle. There are 17 questions.
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...
Curated OER
Inscribing a Hexagon in a Circle
This activity is a follow-on activity to inscribing a square in a circle. The overall problem is more complex. It deals with geometric constructions, properties of triangles, and regular hexagons. The final part of the activity...
Curated OER
Inscribed Right Triangles
Students calculate the measurements of the inscribed angles of a triangle. For this geometry lesson, students relate the hypotenuse of a right triangle and the diameter of a circle to each other. They calculate the diameter of a circle...
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...
Curated OER
Inscribing a Circle in a Triangle
Pupils investigate inscribing a circle in a triangle. They use Cabri Jr. to draw a triangle, locate the incenter, and use the distance from the incenter to a side of the triangle to inscribe a circle. The dynamic nature of the geometry...
Curated OER
Circles
In this circles worksheet, 10th graders solve and complete 8 different types of problems. First, they find the measures of each segment given the center of a circle. Then, students find the length of a side of a triangle shown within a...
EngageNY
Cyclic Quadrilaterals
What does it mean for a quadrilateral to be cyclic? Mathematicians first learn what it means for a quadrilateral to be cyclic. They then investigate angle measures and area in such a quadrilateral.
EngageNY
Thales’ Theorem
Isn't paper pushing supposed to be boring? Learners attempt a paper-pushing puzzle to develop ideas about angles inscribed on a diameter of a circle. Learners then formalize Thales' theorem and use geometric properties to develop a proof...
Curated OER
Volume and Surface Area
In this volume and surface area worksheet, 10th graders solve and complete 12 different types of problems. First, they find the volume and total surface area of a given circle. Then, students find the height and radius of a cylinder...
Curated OER
Circles Terminology Multiple Choice
In this circles activity, students solve 10 multiple choice problems. Students answer questions about diameter and chord relationships, tangent lines to a circle, circumference, the Pi relationship, etc.