CK-12 Foundation
Identify Accurate Drawings of Triangles: Law of Cosines
Drawing triangles is easy, even if you have to calculate the exact length of its sides. Scholars use the Law of Cosines to find missing sides of triangles. An interactive helps them check their answers.
Curated OER
You Can't Go Wrong with a Right Triangle 2
Upper graders use the properties of right angle trignonmetry to measure objects such as the school flagpole. They solve real world problems using these properties.
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Cosine
In this cosine worksheet, 10th graders solve 10 different problems that include various measures of angles. They determine the value of x in each problem using the cosine of the given angle. Then, students substitute the answer they...
Curated OER
Law of Cosines
For this cosine worksheet, students will find the length of the third side of a triangle given the length of the other two side. Students will use the Law of Cosines to find the length of the missing side. Answers will be rounded to 3...
Curated OER
Applications of Triangles
Students 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.
EngageNY
From Circle-ometry to Trigonometry
Can you use triangles to create a circle? Learners develop the unit circle using right triangle trigonometry. They then use the unit circle to evaluate common sine and cosine values.
West Contra Costa Unified School District
Introduction to Trigonometric Functions
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.
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.
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
The Laws of Sines and Cosines Made Simple!
Students explore the concept of law of sines and cosines. In this law of sines and cosines lesson plan, students construct a triangle tool from card stock and markers. Students use their triangle tool to aid in solving problems...
Curated OER
The Law of Cosines
In this Law of Cosines worksheet, students are asked to demonstrate the ability to apply the Trigonometric Law of Cosines and the Inverse Law of Cosines to solve for sides and angles of right triangles.
Curated OER
Right Triangle Geometry
Students study the basic principles of right triangle geometry needed to solve for unknown values of a right triangle. They apply and master the principles of right triangle geometry by solving problems.
Curated OER
Trigonometry Ratios in Right Triangles
For 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...
Curated OER
Law of Sines and Cosines
In this sine and cosine worksheet, students solve given triangles using the law of sines and cosines. They determine the area of triangles. This three-page worksheet contains 12 multi-step problems.
Curated OER
Law of Sines and Law of Cosines
In this sine and cosine worksheet, students use the law of sines and law of cosines to find the required part of a triangle. Examples and explanations are provided. This three-page worksheet contains 24 problems. Answers are listed at...
Curated OER
Area of a Triangle
Students solve the area of triangles. In this precalculus lesson, students are given two sides of a triangle and asked to calculate the area. They apply the law of sine and the side-angle-side area formula to solve.
Curated OER
Law of Sines and Law of Cosines
For this Pre-calculus/Trigonometry worksheet, students use the laws of sines and cosines to solve triangles. The four page worksheet contains thirteen problems. Answers are not included.
Curated OER
Triangles
In this triangles learning exercise, students solve for the missing angles and missing sides on the triangles given. Students complete 12 problems total.
Curated OER
The Sine and Cosine Ratios
For 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.
Curated OER
Right Triangles and The Unit Circle
Young scholars solve right triangles using trigonometry. In this geometry instructional activity, students use the unit circle to identify different trig values. They identify the six trigonometric identities.
Curated OER
Trigonometry Ratios in Right Triangles
In this trigonometry ratios in right triangles worksheet, 10th graders solve 6 different right triangle problems. First, they find the values of x and y in each triangle, rounding each to the nearest tenth. Then, students locate the...
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...
Curated OER
Area of Triangle Using Trigonometry
In this trigonometry activity, students determine the area of triangles using the trigonometry ratios of sine, cosine, and tangent. This one-page activity contains ten problems.
Curated OER
Law of Cosines Practice
Students practice solving problems with non-right triangles. In this precalculus lesson, students define and identify the properties of the Law of Cosine. They solve problems and investigate the history behind Cosine.