Illustrative Mathematics
Illustrative Mathematics: G Gpe Slopes and Circles
The purpose of this task is to lead young scholars through an algebraic approach to a well-known result from classical geometry, namely, that a point X is on the circle of diameter AB whenever angle AXB is a right angle. This consists of...
Texas Instruments
Texas Instruments: Constructing the Diameter of a Circle
Given a circle, students will construct a diameter of the circle. They will use the following theorem: In the same circle, if one chord is a perpendicular bisector of another chord, then the first chord is a diameter.
Illustrative Mathematics
Illustrative Mathematics: G Co, G Srt Seven Circles I
For this task, seven pennies are placed in a circle so that they are all touching one in the center and their neighbors. The question is whether this will work with other equally-sized circles. Aligns with G-SRT.C and G-CO.C.10.
Math Open Reference
Math Open Reference: Thales' Theorem
Learn about Thales' Theorem 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: Geometry: Inscribed Quadrilaterals in Circles
[Free Registration/Login may be required to access all resource tools.] Learn about the Inscribed Quadrilateral Theorem and solve problems involving quadrilaterals inscribed in circles.
CK-12 Foundation
Ck 12: Geometry: Chords in Circles
[Free Registration/Login may be required to access all resource tools.] This concept teaches students four theorems about chords and how to apply them. Students examine guided notes, review guided practice, watch instructional videos and...
CK-12 Foundation
Ck 12: Geometry: Chords in Circles
[Free Registration/Login may be required to access all resource tools.] In this lesson, students apply chord theorems. Students examine guided notes, review guided practice, watch instructional videos and attempt practice problems.
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 Instruments
Texas Instruments: Relationship of Angles to the Circle
In this activity, students recognize the relationship of angles to circles. They study the Inscribed Angle Theorem and its corollaries.
Illustrative Mathematics
Illustrative Mathematics: G C Right Triangles Inscribed in Circles I
This task provides a good opportunity to use isosceles triangles and their properties to show an interesting and important result about triangles inscribed in a circle with one side of the triangle a diameter. The fact that these...
Khan Academy
Khan Academy: Points Inside/outside/on a Circle
Given the center and radius of a circle, determine if a point is inside of the circle, on the circle, or outside of the circle. Students receive immediate feedback and have the opportunity to try questions repeatedly, watch a video or...
Math Open Reference
Math Open Reference: Central Angle Theorem
Learn about the Central Angle Theorem with this handy reference guide. Provides a detailed definition and an interactive activity that enhances further explanation. Includes links to related topics.
Mangahigh
Mangahigh: Shape: Right Angle in a Semi Circle Rule
Test your knowledge of the measurement of angles in a triangle.
Mangahigh
Mangahigh: Shape: Alternate Segment Rule for Circles
Use the alternate segment rule for cirlces to determine the angle measures.
Analyze Math
Analyze Math: Inscribed and Central Angles in Circles
The geometry tutorial investigates the definitions and theorems related to inscribed and central angles in circles. An example with a detailed solution is included.
Cuemath
Cuemath: Central Angle
Learn all about the basic properties of central angles. This lesson targets what is a central angle, central angle formula, central angle calculator, theorem of central angle, how to find central angles, and how to apply them while...
University of Saskatchewan (Canada)
University of Saskatchewan: Geometry
The University of Saskatchewan's Department of Mathematics and Statistics provides high school students with online tutorials and exercises on what they deem some of the most important topics in geometry: Triangles, and Circles and Other...
CK-12 Foundation
Ck 12: Geometry: Segments From Secants
[Free Registration/Login may be required to access all resource tools.] Apply the Two Secants Segments Theorem.
CK-12 Foundation
Ck 12: Geometry: Segments From Secants
[Free Registration/Login may be required to access all resource tools.] This concept teaches students to solve for missing segments from secants intersecting circles.
CK-12 Foundation
Ck 12: Geometry: Segments From Secants and Tangents
[Free Registration/Login may be required to access all resource tools.] This concept teaches students to solve for missing segments created by a tangent line and a secant line intersecting outside a circle.
Cut the Knot
Cut the Knot!: Interactive Mathematics: Geometry Articles, Theorems, Problems
Contains over five hundred Geometry articles, problems, puzzles, and games. Some sites relating to circles are provided within this list.
Illustrative Mathematics
Illustrative Mathematics: G Srt Ask the Pilot
In the July 2013 issue of United Airlines' Hemisphere Magazine, a pilot responded to a question about how far in the distance he could see at different altitudes. The solution involved right triangles, lines of tangency to a circle, and...
Math Is Fun
Math Is Fun: Trigonometry
Students explore trigonometry concepts through this collection of definitions, lessons, examples problem-solving steps and strategies, and practice problems. Topics include solving triangles, trigonometric functions, theorems, and the...
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.