EngageNY
Circles, Chords, Diameters, and Their Relationships
A diameter is the longest chord possible, but that's not the only relationship between chords and diameters! Young geometry pupils construct perpendicular bisectors of chords to develop a conjecture about the relationships between chords...
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...
Teach Engineering
Stay in Shape
Using their knowledge of right triangles, pupils find out how far a ship is from a light house. Class members determine how far around the world a ship would be sailing at a constant speed.
Illustrative Mathematics
Paper Clip
With minimal setup and maximum freedom, young geometers are encouraged to think outside the box on a seemingly simple application problem. Though the task seems simple, measuring a given paper clip and finding how many 10 meters can...
Curated OER
Angles and Arcs
In this angles and arcs worksheet, 10th graders solve 8 different problems that relate to determining the measure of various angles and arcs of a circle. First, they define a central angle and the difference between a major and minor...
Curated OER
From Different Angles
Students participate in Socratic seminar discussing a person's right to refuse to say the Pledge of Allegiance.
Curated OER
Sir Cumference and the First Round Table
In this circumference worksheet, learners solve and complete 5 different figures illustrated on the sheet. First, they cut out each shape found on the bottom. Then, students use the shapes on the left as clues to create the corresponding...
Curated OER
Trig Cheat Sheet
Your pre-calculus learners will make use of this wonderful cheat sheet that summarizes all things trigonometric. Definitions based on both the unit circle and the right triangle are included, as well as many convenient trigonometric...
Lane Community College
Review Sheets: Geometry
Full of problems with polygons, angles, lines, and triangles, your learners get a multi-page packet that provides all they need to know. It contains many of the standard problem types as well as some more challenging questions.
Mathematics Assessment Project
Hopewell Geometry
Right triangles from 2,000 years ago? Learners investigate different right triangles found in the earthworks of the Hopewell people, a Native American culture that populated the United States from 200BC to AD 500. Learners apply concepts...
Curated OER
Cabri Jr. Perpendicular Bisector of a Chord
Your learners will construct the perpendicular bisector of a chord. They use Cabri Jr. to construct a circle and a perpendicular bisector of a chord. They then measure lengths of the chords and perpendicular bisectors. Learners use...
Curated OER
Inscribed Right Triangles
Students calculate the measurements of the inscribed angles of a triangle. For this geometry lesson, students relate the hypotenuse of a right triangle and the diameter of a circle to each other. They calculate the diameter of a circle...
Curated OER
Right Triangles and Unit Circles
Students evaluate the six trigonometric values of a trig function. In this trigonometry lesson, students use the Unit Circle to find the values of right triangles and their angles. They identify an angle of elevation and...
Curated OER
The Unit Circle
Students solve problems using the unit circle. In this precalculus lesson, students identify angles using the properties of the unit circle. They observe the trigonometric graphs and sine, cosine and tangent.
Curated OER
Letter Angles
In this angles in alphabet letters worksheet, 3rd graders study 6 capital letters and answer 8 mathematical questions relating to the angles of each letter.
Curated OER
Angle Land and Angle Aerobics
Sixth graders investigate different types of angles. In this geometry lesson, 6th graders use a protractor to identify acute, obtuse, and straight angles.
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...
EngageNY
Thales’ Theorem
Isn't paper pushing supposed to be boring? Learners attempt a paper-pushing puzzle to develop ideas about angles inscribed on a diameter of a circle. Learners then formalize Thales' theorem and use geometric properties to develop a proof...
EngageNY
Law of Sines
Prove the Law of Sines two ways. The ninth segment in a series of 16 introduces the Law of Sines to help the class find lengths of sides in oblique triangles. Pupils develop a proof of the Law of Sines by drawing an altitude and a second...
Georgia Department of Education
Analytic Geometry Study Guide
Are you looking for a comprehensive review that addresses the Common Core standards for geometry? This is it! Instruction and practice problems built specifically for standards are included. The material includes geometry topics from...
EngageNY
Extending the Domain of Sine and Cosine to All Real Numbers
Round and round we go! Pupils use reference angles to evaluate common sine and cosine values of angles greater than 360 degrees. Once they have mastered the reference angle, learners repeat the process with negative angles.
Curated OER
Math Handbook: Trigonometry
You'll be spinning in unit circles once you read through this jumbo-sized resource of everything you need to know about trigonometry. Each page has color-coded examples with explicit directions that detail the problems and...
Curated OER
Crossword: Geometric Shapes
Using a word bank, mathematicians fill out a crossword puzzle using 9 clues. Each clue describes a shape, using details such as the number of sides, angle degrees, and the shape category. For example: "A quadrilateral with four equal...
Curated OER
Unit Circle and Triangle
Students apply the Unit Circle to solve ratios of triangles. In this geometry lesson, students derive the different ratios of a triangle using the Pythagorean Theorem. They find the angles of a unit circle using a right triangle.