Flipped Math
Unit 11 Review: Circles
Solve problems around a circle. Pupils watch a video that shows how to apply concepts about circles and related angles and segments to find solutions to word problems. Learners then review the different concepts from the unit in...
Curated OER
Measuring the Earth
Students identify types of arcs and angles in a circle, find the measure of arcs and angles, and solve real world problems involving lengths of segments in circles, lengths, and areas.
Curated OER
Solving Intercepted Arcs
Students investigate circles and its arcs. In this geometry activity, students identify the relationship between an circle and its intercepted arcs. THey identify the central and inscribed angles.
EngageNY
Geometry Module 5: End-of-Module Assessment
The lessons are complete. Learners take an end-of-module assessment in the last installment of a 23-part module. Questions contain multiple parts, each assessing different aspects of the module.
Curated OER
Circle Proofs
In this circle proofs worksheet, 10th graders complete 4 different problems that include circle proofs. They respond to each of the questions that deal with circle proofs. Then, students read the given information and use the circle...
Curated OER
Circle Packing
Students identify different parts and properties of circles. In this geometry lesson, students identify the radius, diameter, semicircle and inscribed angle of a circle. They identify the tangent lines to a circle.
Curated OER
Math: Tangents
Students discover how to recognize tangents and how to use their properties.  They investigate and use the properties of angles, arcs, chords, tangents, and secants.  Students use two tangents and the properties of similar triangles to...
Curated OER
Angles and Arcs
Students discuss the sum of central angles and use string to create them on circles.  They find the measure and length of both minor and major arcs.
Students give examples of concentric, similar, and congruent circles and congruent arcs.
Curated OER
DEAD MAN'S CURVE
Ninth graders, after being given a unique scenario and a task sheet on Dead Man's Curve, calculate and explain the force needed to keep a car on a curve using a set of formulas and a geometric property of circles. They utilize and create...
Curated OER
Geometry Regents Bimodal
In this geometry activity, students solve problems that are bimodal. They define properties of circles and triangles. There are 117 questions.
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
Circle Terminology
In this geometry worksheet, students identify radii, diameters, chords, tangents, secants and other terminology associated with circles.  The one page worksheet contains eighteen problems.  Answers are not provided. 
Texas Instruments
Texas Instruments: Angles Formed by Intersecting Chords, Secants, and Tangents
In this activity, students will investigate properties of angles and arcs formed when chords, secants, and tangents intersect and intercept arcs in a circle. They discover several important theorems concerning circles and arc sizes. They...
Texas Instruments
Texas Instruments: Chords, Secants, and Tangents
Young scholars construct chords, secants, and tangents. From those constructions, they develop a deeper understanding of the terms, as well as explore certain properties of the constructions.
Texas Instruments
Texas Instruments: Segments Formed by Intersecting Chords, Secants, and Tangents
This activity is designed to help students discover several important theorems concerning lengths of segments formed by intersecting chords, secants, and tangents.
CK-12 Foundation
Ck 12: Geometry: Circles: Segments and Lengths Study Guide
This study guide on circles covers some vocabulary and theorems about segments and lengths. It is available for download with free registration.
Texas Education Agency
Texas Gateway: Making Conjectures About Circles and Segments
Given examples of circles and the lines that intersect them, the student will use explorations and concrete models to formulate and test conjectures about the properties and relationships among the resulting segments.
Oswego City School District
Regents Exam Prep Center: Circles, Segments, and Area
A wealth of resources to supplement instruction on parts of the circle. Find lessons describing chords, tangents, secants, and segments, as well as related practice quizzes and classroom activities.
Math Open Reference
Math Open Reference: Circles
A complete reference guide to circles including parts, angles, and arcs. It provides definitions and interactive activities that enhance further explanation.
Math Planet
Math Planet: Geometry: Advanced Information About Circles
Provides advanced information about circles through the use of examples and a brief video lesson. [1:00]