Curated OER
Special Right Triangles
Using the Pythagorean Theorem to solve for missing angles, students evaluate right triangles and their properties.
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...
Mathematics Assessment Project
Inscribing and Circumscribing Right Triangles
High schoolers attempt an assessment task requiring them to find the radii of inscribed and circumscribed circles of a right triangle with given dimensions. They then evaluate provided sample responses to consider how to improve...
Curated OER
Solving Right Triangles
Students investigate the basic trigonometric functions. In this geometry/trigonometry lesson, students explore strategies to solve right triangles using basic trigonometric functions. The lesson includes an application...
Curated OER
Finding the Area of an Equilateral Triangle
The problem seems simple: find the area of the equilateral triangle whose sides are each length 1. In fact, this same problem is solved in 8th grade, addressing a different Common Core standard, using the formula for area of a triangle...
EngageNY
Solving Problems Using Sine and Cosine
Concepts are only valuable if they are applicable. An informative resource uses concepts developed in lessons 26 and 27 in a 36-part series. Scholars write equations and solve for missing side lengths for given right triangles....
Mathematics Vision Project
Similarity and Right Triangle Trigonometry
Starting with similar triangles and dilation factors, this unit quickly and thoroughly progresses into the world of right triangle features and trigonometric relationships. Presented in easy-to-attack modules with copious application...
Curated OER
Right Triangles and The Unit Circle
Learners solve right triangles using trigonometry. In this geometry lesson, students use the unit circle to identify different trig values. They identify the six trigonometric identities.
Curated OER
Right Triangles and The Pythagorean Theorem
Students play a game to reinforce concepts of the Pythagorean Theorem. In this geometry lesson, students find the missing angle and lengths of a right triangle. They use properties of trigonometry about sine, cosine and tangent to solve...
EngageNY
Using Trigonometry to Find Side Lengths of an Acute Triangle
Not all triangles are right! Pupils learn to tackle non-right triangles using the Law of Sines and Law of Cosines. After using the two laws, they then apply them to word problems.
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
Right Triangles and Unit Circles
Pupils 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 depression.
Curated OER
Geometry Exploration Basic Trig Functions
Tenth graders solve for missing sides on a triangle using the Pythagorean Theorem. In this geometry lesson, 10th graders are introduced to basic trigonometry functions as they solve problems of right triangles. They discuss the...
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...
Curated OER
Altitude to the Hypotenuse
Can your class solve right triangles and identify the properties common to right triangles? They will investigate and state the relationship between the altitude to the hypotenuse and the two segments of the hypotenuse formed by the...
Mathematics Vision Project
Module 7: Trigonometric Functions, Equations, and Identities
Show your class that trigonometric functions have characteristics of their own. A resource explores the features of trigonometric functions. Learners then connect those concepts to inverse trigonometric functions and trigonometric...
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
Applications of Triangles
Learners apply the properties of a right triangle. In this triangle instructional activity, students describe and compare radians to degrees. They solve problems using the properties and ratios of a right triangle.
Curated OER
Trig Review
Twelfth graders review the 6 identities of trigonometry. In this trig lesson plan, 12th graders review the importance of the right triangle as it relates to sine, cosine and tangent. They review the basic trig identities and how it...
EngageNY
Trigonometry and the Pythagorean Theorem
Ancient Egyptians sure knew their trigonometry! Pupils learn how the pyramid architects applied right triangle trigonometry. When comparing the Pythagorean theorem to the trigonometric ratios, they learn an important connection that...
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...
Shodor Education Foundation
Pythagorean Theorem
Most adults remember learning about the Pythagorean theorem, but they don't all remember how to use it. The emphasis here is on developing an intuitive understanding of how and when to use the theorem. Young mathematicians explore...
Curated OER
How Far Am I Traveling
Students solve for missing sides using the Pythagorean theorem. In this algebra lesson, students derive the six trigonometric values using the right triangle. They relate the Pythagorean theorem to the distance formula.
Curated OER
The Tangent Ratio
Students calculate the tangent ratio given a right triangle. In this trigonometry lesson, students use a right triangle and the Pythagorean Theorem to solve problems.