Illustrative Mathematics
The Lighthouse Problem
Long considered the symbol of safe harbor and steadfast waiting, the lighthouse gets a mathematical treatment. The straightforward question of distance to the horizon is carefully presented, followed by a look into the...
Alabama Learning Exchange
"I Saw the Sine"
Discover trigonometric ratios that complement each other. Using two videos, the lesson introduces the trigonometric ratios. The class discovers the relationship between the sine and cosine of complementary angles.
Virginia Department of Education
Special Right Triangles and Right Triangle Trigonometry
Right triangles are so special! Use special right triangles to discover the trigonometric ratios. Pairs construct special right triangles and find the values of the ratios of the sides. In the process, they discover the ratios stay the...
Curated OER
Which Triangles are Right
Students apply properties of right triangles to solve problems. In this geometry lesson plan, students identify axioms and theorems using examples.
Curated OER
Understanding Fundamental Trigonometric Identities
Young scholars 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...
Curated OER
Finding Patterns in Fractals
Students discover patterns and sequences. They use a website to explore patterns and fractals. Students share their discovery of fractals and their patterns with the class. They develop a list of patterns used in everyday life.
Discovery Education
Exploring Geometry
Middle schoolers construct a three-dimensional model of a city using both similar and congruent figures and geometric transformations. City must have at least ten buildings with each building labeled and may be constructed out of paper...
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.
Curated OER
Connecting Formulas Related to Geometric Figures
Young scholars identify diagrams of quadrilaterals and circles by different names and classify the figures. They name the areas for each diagram and practice solving the formulas for each.
Curated OER
Plenty of Pythagoras
Using a twelve foot knotted rope, students form a 3-4-5 right triangle. Following a discussion of observations about the lengths of the sides of the triangle, students use grid paper, scissors and a centimeter ruler to draw and measure...
Curated OER
Geometry Shapes Playground Safety
Students create a new playground design to present to elementary students during Playground safety week. They review basic geometry to use in observing and recording the equipment on a local playground. They research playground safety...
Curated OER
Translating Transformations in Geometry
Students create an image using given coordinates and evaluate how the coordinates change when a slide or rotation takes place.
Curated OER
Special Right Triangles
Students identify different types of special right triangles. In this geometry lesson, students differentiate between right triangles and isosceles triangles. they construct the triangles using geometry software and make conjectures...
Curated OER
The Overlooked Regular Pentagon
Tenth graders discuss the history of geometry as it relates to pentagons. In this geometry lesson, 10th graders solve problems of a pentagon inscribed inside of a circle using ratio. They review other properties for shapes of polygons...
Oswego City School District
Regents Exam Prep Center: Pythagorean Theorem
Who was Pythagoras and what is his theorem? Explore this concept and its relationship to the measurement of a right triangle in this test prep lesson plan. The lesson includes an interactive worksheet where learners discover the answers...
TeachEngineering
Teach Engineering: Handheld Trigonometry
In addition to understanding the concept of similar right triangles and how they apply to trigonometric ratios, students explore a clinometer app, and discover how it can be used to test the mathematics underpinning trigonometry.