Lesson Plan
EngageNY

Sine and Cosine of Complementary Angles and Special Angles

For Students 9th - 10th Standards
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...
Lesson Plan
Curated OER

The Laws of Sines and Cosines Made Simple!

For Teachers 10th - 12th
Students study the law of sine and cosine. In this pre-calculus lesson, students create a triangle and identify the different ratios of a non-right triangle. They use the properties of sine and cosine to solve.
Lesson Plan
Alabama Learning Exchange

"I Saw the Sine"

For Teachers 9th - 12th Standards
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.
Lesson Plan
EngageNY

What Is a Trigonometric Identity?

For Students 10th - 12th Standards
Protect yourself from identity theft! Establishing a strong understanding of the Pythagorean identity allows learners to prove that sine^2x + cos^2x = 1. They then use the identity to find sine or cosine ratios given the other.
Worksheet
Curated OER

The Sine and Cosine Ratios

For Students 10th
In this geometry worksheet, 10th graders write the ratio that represents the sine and cosine of the indicated angle.  The one page worksheet contains two multiple choice questions.  Answers are included. 
Worksheet
Curated OER

Sine, Cosine, and Tangent Ratios

For Students 11th
In this ratios learning exercise, 11th graders solve and complete 8 various types of problems. First, they read each problems and draw a sketch for each. Then, students write a trigonometric ratio for each problem and round any decimal...
Lesson Plan
EngageNY

The Definition of Sine, Cosine, and Tangent

For Students 9th - 10th Standards
Introduce your classes to a new world of mathematics. Pupils learn to call trigonometric ratios by their given names: sine, cosine, and tangent. They find ratios and use known ratios to discover missing sides of similar...
Interactive
CK-12 Foundation

Fundamental Trigonometric Identities: Tangent Identity

For Students 10th - 12th
An identity that thieves can't steal  the tangent identity. Scholars manipulate ratios to investigate the tangent ratio and connect it to the sine and cosine ratios. An interactive that uses color coding helps with this task.
Unit Plan
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Mathematics Vision Project

Similarity and Right Triangle Trigonometry

For Teachers 10th - 12th Standards
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...
Lesson Plan
EngageNY

Trigonometry and the Pythagorean Theorem

For Students 9th - 11th Standards
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...
Lesson Plan
West Contra Costa Unified School District

Introduction to Trigonometric Functions

For Teachers 9th - 12th
Scholars first learn the definitions of the sine ratio, the cosine ratio, and the tangent ratio. After mastering these definitions, they use the new information to solve triangles.
Lesson Plan
Virginia Department of Education

Special Right Triangles and Right Triangle Trigonometry

For Teachers 9th - 11th Standards
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...
Lesson Plan
EngageNY

Why Call It Tangent?

For Students 10th - 12th Standards
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...
Assessment
Illustrative Mathematics

Finding Trig Values

For Students 9th - 12th Standards
Let's keep trigonometry simple. When given a cosine ratio, learners must use the clues about the quadrant to determine the sine and tangent ratios. The answer key has a complete worked-out solution to help guide pupils through the...
Interactive
CK-12 Foundation

Tangent Graphs: Slope and Angle

For Students 10th - 12th Standards
Learning about tangents doesn't have to be a slippery slope. Pupils drag a point around a unit circle to see how angle affects the slope of a line. They individually answer a set of challenge questions to come to the conclusion that...
Lesson Plan
EngageNY

Between-Figure and Within-Figure Ratios

For Teachers 9th - 10th Standards
Tie the unit together and see concepts click in your young mathematicians' minds. Scholars apply the properties of similar triangles to find heights of objects. They concentrate on the proportions built with known measures and solve to...
Worksheet
Curated OER

Right Triangle Trigonometry: Finding Missing Sides and Angles

For Students 9th - 11th
In this right triangle trigonometry worksheet, students find the measure of specified angles. Students determine the length of the missing side of a right triangle. This four-page worksheet contains 24 problems. Answers to the worksheet...
Lesson Plan
EngageNY

Unknown Angles

For Students 9th - 10th Standards
How do you solve an equation like trigonometry? Learners apply their understanding of trigonometric ratios to find unknown angles in right triangles. They learn the meaning of arcsine, arccosine, and arctangent. Problems include...
Worksheet
Curated OER

Trigonometry Ratios in Right Triangles

For Students 10th
In this trigonometry ratios in right triangles worksheet, 10th graders solve 10 different trigonometric ratios that apply to right triangles. First, they define a trigonometric ratio and its three most common ratios, sine, cosine, and...
Worksheet
Curated OER

Law of Sines

For Students 10th - 12th
In this Law of Sines worksheet, students use trigonometric ratios to determine angle measurement and/or the length of the side of a triangle. This one-page worksheet contains ten trigonometric ratio problems.
Lesson Plan
Curated OER

Trigonometry Ratios

For Teachers 9th - 12th Standards
High schoolers identify the different angles and sides of a triangle. In this geometry lesson, students identify the six trigonometric ratios. They graph the graph of each trig function and analyze it.
Worksheet
Curated OER

Cosine

For Students 10th - 12th
In this cosine worksheet, students find the cosine of x for different measurements of triangles. Students complete 10 cosine problems.
Worksheet
Curated OER

Using Trinonometry to Find Angle Measures

For Students 10th - 12th
In this trigonometric ratios worksheet, students find the missing angle of 20 triangles by using sine, cosine and tangent ratios. Students compute the angle measurement of given ratios for six problems.
Worksheet
Curated OER

Missing Angles

For Students 10th - 11th
For this missing angle worksheet, students use trigonometry ratios to determine the measurement of a missing angle. Students identify sine, cosine and tangent ratios. This one-page worksheet contains ten problems.