Khan Academy
Khan Academy: Determining Tangent Lines: Lengths
Solve two problems that apply properties of tangents to determine if a line is tangent to a circle.
Khan Academy
Khan Academy: Determining Tangent Lines: Angles
Solve two problems that apply properties of tangents to determine if a line is tangent to a circle.
CK-12 Foundation
Ck 12: Tangent Lines
[Free Registration/Login Required] Students can adjust the size of the circle to explore the tangent lines. Click learn more to watch a video and click challenge me to answer a practice question.
Cuemath
Cuemath: Tangent
Learn about the tangent definition in geometry, tangent geometry, tangent to a circle, tangent line equation. Check-out the solved examples for better understanding and try your hand at the tangent line calculator or solving a few...
Illustrative Mathematics
Illustrative Mathematics: G C, G Co Tangent Lines and the Radius of a Circle
In this task, students are shown a circle with center O and point P on the circle. L is a line that is a tangent to the circle at P. They must show that line OP is perpendicular to line L. Aligns with G-C.A.2, G-CO.A, and G-CO.C.9.
Geometry Help
Geometry Help: Tangent Lines
Explains the basic concept of congruent triangles with step-by-step instructions and methods for solving specific problems on your own relating to this topic.
CK-12 Foundation
Ck 12: Geometry: Angles on and Inside a Circle Intermediate
[Free Registration/Login may be required to access all resource tools.] This concept teaches students how to find angles on and inside a circle created by chords and tangent lines.
Government of Alberta
Learn Alberta: Math Interactives: Exploring Circle Geometry Properties
Investigate circles, namely their angles, chords, and tangents using this highly interactive Learn Alberta math. Explore a number of circle geometry properties that can be used to determine unknowns. Be sure to follow the link to the...
Illustrative Mathematics
Illustrative Mathematics: G C Tangent to a Circle From a Point
This task builds on a previous one called ''Right triangles inscribed in circles I.'' Here students are asked to construct a tangent line to a circle from a point outside of the circle. Aligns with G-C.A.4.
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.
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.
CK-12 Foundation
Ck 12: Geometry: Angles Outside a Circle Intermediate
[Free Registration/Login may be required to access all resource tools.] This concept teaches students how to calculate angles formed outside a circle by tangent and secant lines.
CK-12 Foundation
Ck 12: Geometry: Properties of a Circle Study Guide
[Free Registration/Login may be required to access all resource tools.] This study guide reviews the terminology for circles (tangent, arcs, central angles) and the equation for a circle.
BBC
Bbc: The Circle
The equation of a circle is the focus of this site. Topics include tangents, intersecting circles, and intersection of lines and circles. Examples and a practice test are available.
Texas Instruments
Texas Instruments: Relationship Between Radius and Tangent to a Circle
Generalize that a tangent and a radius form a 90-degree angle.
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.
ClassFlow
Class Flow: Circles Geometry
[Free Registration/Login Required] Students identify segments and lines related to circles and the properties of a tangent to a circle.
Sophia Learning
Sophia: Two Lines Tangent to a Circle: Lesson 3
This lesson will present how if two segments from the same point outside a circle are tangent to a circle, then they are congruent. It is 3 of 5 in the series titled "Two Lines Tangent to a Circle."
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...
Other
Ctte: Geometer's Sketch Pad Activities
This site offers numerous activities for middle school and high school students to explore using Geometer's Sketch Pad.
Ministry of Education and Universities of the Region of Murcia (Spain)
Ministerio De Educacion Y Ciencia: Tangencias
In Spanish. This interactive unit introduces various geometric concepts which are intended to be tools for solving problems of tangencies between straight lines, circles and points.