EngageNY
Special Triangles and the Unit Circle
Calculate exact trigonometric values using the angles of special right triangles. Beginning with a review of the unit circle and trigonometric functions, class members use their knowledge of special right triangles to find the value of...
Mathematics Vision Project
Circles: A Geometric Perspective
Circles are the foundation of many geometric concepts and extensions - a point that is thoroughly driven home in this extensive unit. Fundamental properties of circles are investigated (including sector area, angle measure, and...
Alabama Learning Exchange
Unit Circle: Special Angles—Just Know One
It's all about the patterns! Young scholars learn that the unit circle repeats itself in all four quadrants. Using these patterns, they evaluate the sine, cosine, and tangent of special angles.
Illustrative Mathematics
Slopes and Circles
An upper-level treatment of what is often presented as a basic concept (the right angle of an inscribed circle on the diameter), this activity really elevates the mathematical thought of the learner! Expected to develop formulas from...
CK-12 Foundation
Trigonometric Functions and Angles of Rotation: The Triangle in the Circle
Go around the unit circle and create triangles. Pupils move a point around the unit circles to visualize the triangle associated with the angle in standard position. The three main trigonometric functions are defined in terms of the legs...
Mathematics Assessment Project
Sorting Equations of Circles 2
How much can you tell about a circle from its equation? This detailed lesson plan focuses on connecting equations and graphs of circles. Learners use equations to identify x- and y-intercepts, centers, and radii of circles. They also...
Math Stars
Math Stars: a Problem-Solving Newsletter Grade 8
You've just hit the jackpot of integrating math problems and riddles with this jumbo-sized resource! Written as a newsletter, scroll through 35 pages of puzzles and quality problems to engage and encourage your learners to inquire and...
Curated OER
Tangent Lines and the Radius of a Circle
Your Geometry learners will collaboratively prove that the tangent line of a circle is perpendicular to the radius of the circle. A deliberately sparse introduction allows for a variety of approaches to find a solution.
Houghton Mifflin Harcourt
Developing Formulas for Circles and Regular Polygons
Formulas and procedures for finding the area and circumference are not provided on this handout, so it will be best used as a practice of already-acquired skills. It is a well-rounded assignment, however, as it includes diagrams,...
EngageNY
Why Call It Tangent?
Discover the relationship between tangent lines and the tangent function. Class members develop the idea of the tangent function using the unit circle. They create tables of values and explore the domain, range, and end behavior of the...
Curated OER
Chapter 8: Circles
In this circles activity, students define and sketch 20 terms about circles. Students sketch radii, chords, diameters, secants, concentric circles, etc.
Curated OER
The Geometry of Circles
Students review the parts of a circle, calculate the circumference and area of a circle, and create student-made tests on the geometry of circles using educational software.
Curated OER
Discovering Pi
Define terminology related to a circle. Practice accuracy in measuring and then create a spreadsheet based on data collected from solving for parts of a circle. Groups can have fun analyzing their data as it relates to Pi.
Mathematics Vision Project
Module 6: Trigonometric Functions
Create trigonometric functions from circles. The first lesson of the module begins by finding coordinates along a circular path created by a Ferris Wheel. As the lessons progress, pupils graph trigonometric functions and relate them to...
Mathed Up!
Area of Sector and Length of Arcs
Viewers learn how to apply proportional reasoning to find area of sectors and arc lengths with a video that starts off explaining how to find the areas of circle sectors and the lengths of arcs. Scholars then practice solving problems...
EngageNY
The Motion of the Moon, Sun, and Stars—Motivating Mathematics
What does math have to do with the behavior of the earth and sun? Learn how the movement of celestial bodies has influenced the development of trigonometry. Scholars connects the details in mathematics to their real-world meaning.
Curated OER
Transformations in the Coordinate Plane
Your learners connect the new concepts of transformations in the coordinate plane to their previous knowledge using the solid vocabulary development in this unit. Like a foreign language, mathematics has its own set of vocabulary terms...
EngageNY
Ferris Wheels—Using Trigonometric Functions to Model Cyclical Behavior
Have class members going in circles as they model the path of a Ferris Wheel using trigonometric functions. Building on the previous lesson in this series on transformations, learners use trigonometric functions to model wheels of...
PHET
Trig Tour
Unit circles and trigonometric graphs go hand in hand. Pupils see how traversing the unit circle allows for the creation of graphs for trigonometric functions. They also see trigonometric ratios in terms of the ordered pairs of points on...
Curated OER
Calculate Area Using Pi
Geometers find the area of four circles given their circumferences. Circumference is presented in the form of "numeral (diameter) x pi"; the answer key shows solutions as "numeral (radius squared) x pi," so computation is limited to...
Curated OER
Area of Circle Worksheets
In this geometry learning exercise, 10th graders calculate the area of circle give either the radius or the diameter. The one page interactive learning exercise contains ten questions. Answers and hints are included.
Curated OER
Circle Problems - Radius, Diameter, Circumference and Area
In this online math learning exercise, students determine the radius, circumference, diameter and area of circles. This excellent resource allows the students to check their answers, and to get "hints" should they run into difficulties....
Curated OER
Perimeter of Circle Worksheet
In this perimeter worksheet, students find the perimeter of a circle. This two-page worksheet contains 4 problems. Answers are provided on the last page.
Curated OER
Circles
Tenth graders explore and define the radius and diameter of a circle. In this geometry lesson, 10th graders calculate the circumference and area of a circle using real world objects and shapes. They discuss chords and lines tangent to a...