EngageNY
Special Relationships Within Right Triangles—Dividing into Two Similar Sub-Triangles
Why are right triangles so special? Pupils begin their study of right triangles by examining similar right triangles. Verifying through proofs, scholars recognize the three similar right triangles formed by drawing the altitude. Once...
Shodor Education Foundation
Triangle Area
While the lesson focuses on right triangles, this activity offers a great way to practice the area of all triangles through an interactive webpage. The activity begins with the class taking a square paper and cutting in in half; can they...
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.
Curated OER
Special Right Triangles
Students identify the different parts of a right triangle. In this geometry lesson, students use the Pythagorean Theorem to identify missing sides and angles of a right triangle. They work with irrational and rational roots.
EngageNY
Sine and Cosine of Complementary Angles and Special Angles
Building trigonometric basics here will last a mathematical lifetime. Learners expand on the previous lesson in a 36-part series by examining relationships between the sine and cosine of complementary angles. They also review the...
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...
Mathematics Assessment Project
Solving Problems with Circles and Triangles
After completing a task involving examining the ratio of areas of triangles and circles in a given figure, scholars examine sample responses to identify other strategies they could use to solve the problem.
Curated OER
Geometric Properties
High schoolers find triangular angles using the angle theorem. In this geometry instructional activity, students describe labeled triangles, use the pythagorean theorem, and rewrite information about triangles in standard form.
Curated OER
Inscribed Right Triangles
Students calculate the measurements of the inscribed angles of a triangle. In 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 as...
Mathematics Vision Project
Module 5: Modeling with Geometry
Solids come in many shapes and sizes. Using geometry, scholars create two-dimensional cross-sections of various three-dimensional objects. They develop the lesson further by finding the volume of solids. The module then shifts...
EngageNY
Special Lines in Triangles (part 2)
Medians, midsegments, altitudes, oh my! Pupils study the properties of the median of a triangle, initially examining a proof utilizing midsegments to determine the length ratio of a median. They then use the information to find missing...
Curated OER
Pythagorean Theorem
Students discover the Pythagorean Theorem. For this discovering the Pythagorean Theorem lesson, students measure the lengths of various triangles to the nearest centimeter. Students record their measurements in a table. ...
Curated OER
Pythagorean Theorem
Pupils apply properties of Pythagorean to solve problems. In this geometry activity, students identify the different parts of a right triangle using ratios. they solve problems using squares and square roots.
Mathematics Assessment Project
Pythagorean Triples
What special relationships exist in right triangles? In the high school performance task, learners investigate Pythagorean triples. They then determine rules for the perimeter and area of right triangles given the shortest side.
101 Questions
Catcher to 2nd
Who's on second? Young mathematicians use a diagram of a baseball field to find the distance a catcher must throw to reach second base. A brief video of such a play during a baseball game sets the stage for the assignment.
Curated OER
Introduction to Trigonometry
Students identify the six trigonometric ratios and properties. In this trig instructional activity, students define basic trig functions as it relates to solving right triangles. They identify the equation for sine as o/h and cosine as...
Curated OER
How are Trig Ratios Used to Measure Triangle Sides
Students identify the ratios of trig identities. In this geometry lesson, students solve the missing sides and angles of triangles using trig ratios. They relate the graphs and waves to real life scenarios.
Curated OER
Studying Special Segments in Triangles
Students investigate special segments in triangles. In this geometry lesson plan, students graph, compare, estimate and predict findings based on their data. They differentiate between similarity and congruence of triangles.
Curated OER
Exploring Geometric Mean
Students solve problems using geometric means. In this geometry lesson, students create altitudes in right triangles. They use Cabri software to move the triangle around and observe different sides and angles.
Curated OER
Exploring Geometric Mean
Student identify the solution using geometric mean. In this geometry lesson, students create right triangles where the altitude of the triangle is the side containing the right angle. They modify shapes using Cabri software and observe...
EngageNY
Complex Numbers and Transformations
Your learners combine their knowledge of real and imaginary numbers and matrices in an activity containing thirty lessons, two assessments (mid-module and end module), and their corresponding rubrics. Centered on complex numbers and...
Curated OER
The Sum of All Angles
Students add up the different angles using the angle addition postulate. In this geometry lesson, students differentiate between interior and exterior angles. They calculate the different angles for triangles and use proof to show their...
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...
Curated OER
Time Dilation and Geometry
Students solve problems of dilation and velocity. For this geometry lesson, students apply the Pythagorean Theorem to solve problems and relate it to time and velocity.