Concord Consortium
Outward Bound
Just how far can I see? The short assessment question uses the Pythagorean Theorem to find the distance to the horizon from a given altitude. Scholars use the relationship of a tangent segment and the radius of a circle to find the...
Curated OER
Segment Formulas Multiple Choice
In this geometry activity, 10th graders use the theorems regarding circles and tangents to find the indicated missing segment length. The one page interactive activity contains ten problems. Answers are included.
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
Unit Circle Triangle
Students find the different ratios of a right triangle. For this geometry lesson, students apply the concept of the Pythagorean theorem as they identify the different angles and parts of a Unit Circle. They find the ratios of sine,...
Virginia Department of Education
High School Mathematics Geometry Vocabulary Word Wall Cards
Having a good working knowledge of math vocabulary is especially important for geometry learners. Here are 119 pages worth of wonderfully constructed definitions, constructions, formulas, properties, theorems, and postulates. This is a...
Curated OER
Task: Grain Storage
Farming is full of mathematics, and it provides numerous real-world examples for young mathematicians to study. Here, we look at a cylinder-shaped storage silo that has one flat side. Given certain dimensions, students need to determine...
Curated OER
Hexagoning the Circle
Students explore similarity to see that the area of a circle should be a constant times the square of its radius. Students create a hexagon. Students share their designs with the class.
Virginia Department of Education
Arc Length and Area of a Sector
What do skateboarding and baked goods have in common with math? You can use them to connect half-pipe ramps and cakes to arcs and sectors. Pupils compare the lengths of three different ramp options of a skate park. They calculate the...
Curated OER
Understanding Fundamental Trigonometric Identities
Students are introduced to the basic trigonometric identities. Using a diagram, they discover why the parts of the unit circle as named as they are and use equations to finalize the Pythagorean trigonometric identities. They also review...
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
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
Math: Arcs and Chords
Students draw diagrams demonstrating how it is possible to two central angles to be congruent and their minor arcs are not congruent. In groups, they illustrate theorems with their constructed circles, create diameters of circles that...
Curated OER
Inverse and Converse
In this geometry worksheet, students identify given statements for the inverse, converse and contra-positive of a conditional statement. There are 9 questions with an answer key.
Curated OER
Investigating the Idea of Tan
Fifth graders use tan to solve problems involving right-angled triangles. They solve equations of the form tan(8) =a, for a between 180 degrees and 360 degrees. They state the value of tan (8) in special cases.
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.
CK-12 Foundation
Ck 12: Geometry: Angles on and Inside a Circle
[Free Registration/Login may be required to access all resource tools.] Solve problems containing angles on or inside a circle.
Cut the Knot
Cut the Knot!: Monge's Theorem of Three Circles and Common Tangents
Very good site presenting a Trig problem dealing with tangents lines and circles, then linking the student to the solution
Illustrative Mathematics
Illustrative Mathematics: G C, G Co Tangent Lines and the Radius of a Circle
In this task, learners 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.
Mangahigh
Mangahigh: Shape: Radius and Tangent Rule for Circles
Determine the rules for radius and tangents of 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.
CK-12 Foundation
Ck 12: Geometry: Tangent Lines
[Free Registration/Login may be required to access all resource tools.] This concept teaches students about tangent lines and how to apply theorems related to tangents of circles.
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: 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.
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.