CK-12 Foundation
Ck 12: Geometry: Arcs and Angles Study Guide
This study guide on arcs and angles covers key vocabulary, arc measurement in degrees and radians, congruent arcs, bisecting arcs, and the angles on, inside, and outside a circle. Also covers formulas and theorems. It is available for...
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.
CK-12 Foundation
Ck 12: Geometry: Inscribed in Circles Study Guide
This study guide on circles covers some vocabulary terms, and inscribed angles and polygons. It is available for download with free registration.
National Council of Teachers of Mathematics
Nctm: Illuminations: Angle Bisector
This interactive demonstrates how to bisect an angle.
Math Open Reference
Math Open Reference: Central Angle
A handy reference guide to central angles. It provides definitions, examples, and an interactive activity that enhances further explanation. Includes links to related topics.
Math Open Reference
Math Open Reference: Parts of a Circle
Learn about parts of a circle with this pictorial index. Click on the diagrams for more information. Includes links to related topics.
Geometry Help
Geometry Help: Intersecting Lines and Angles
Explains the basic concept of intersecting lines and angles with step-by-step instructions and methods for solving specific problems on your own relating to this topic.
Geometry Help
Geometry Help: Inscribed Shapes
Explains the basic concept of inscribed shapes with step-by-step instructions and methods for solving specific problems on your own relating to this topic.
Geometry Help
Geometry Help: Chords
Explains the basic concept of chords with step-by-step instructions and methods for solving specific problems on your own relating to this topic.
Geometry Help
Geometry Help: Arcs, Angles, and Sectors
Explains the basic concept of arcs, angles, and sectors with step-by-step instructions and methods for solving specific problems on your own relating to this topic.
Geometry Help
Geometry Help: Circles
Explains the basic concept of circles with step-by-step instructions and methods for solving specific problems on your own relating to this topic.
Geometry Help
Geometry Help: Square Inscribed in a Circle
Explains the basic concept of a square inscribed in a circle with step-by-step instructions and methods for solving specific problems on your own relating to this topic.
Math Open Reference
Math Open Reference: Inscribed Angle
Learn about inscribed angles with this handy reference guide. Provides a detailed definition, examples, and an interactive activity that enhances further explanation. Includes links to related topics.
Math Open Reference
Math Open Reference: Chord
Learn about chords with this handy reference guide. Provides a detailed definition, examples, and an interactive activity that enhances further explanation. Includes links to related topics.
CK-12 Foundation
Ck 12: Interactive Geometry: 8.5 Inscribed and Circumscribed Circles of Triangle
Learn how an inscribed circle is the largest circle contained within the triangle.
CK-12 Foundation
Ck 12: Interactive Geometry: 8.4 Inscribed Angles
Learn about inscribed angles formed by two chords in a circle which have a common endpoint.
CK-12 Foundation
Ck 12: Interactive Geometry: 8.3 Central Angles and Chords
Learn and understand central angles and chords.
Khan Academy
Khan Academy: Inscribed Angle Theorem Proof
Proving that an inscribed angle is half of a central angle that subtends the same arc.
Khan Academy
Khan Academy: Challenge Problems: Inscribed Angles
Solve two challenging problems that apply the inscribed angle theorem to find an arc measure or an arc length.
University of Georgia
University of Georgia: Altitudes & Orthocenters: Making Connections
This site describes altitudes and orthocenters in triangles and their connections with the nine-point circle.
Math Words
Mathwords: Inscribed Circles
Mathwords provides an explanation and a diagram of an inscribed circle. By clicking on any of the highlighted words, you will learn about related terms.
The Math League
The Math League: Angles and Angle Terms: Angle Bisector
A tutorial on angles with definitions, examples, and pictures.
Free Math Help
Free Math Help: Special Pairs of Angles
The lesson investigates special pairs of angles. Topics explored include complementary, supplementary, and vertical angles. Students learn about the concept and view diagrams and exercises with solutions.
Varsity Tutors
Varsity Tutors: Hotmath: Algebra Review: Chord
Find a quick, concise explanation of a chord. Examples are illustrated and explained.