EngageNY
Putting the Law of Cosines and the Law of Sines to Use
Use the Law of Cosines and the Law of Sines to solve problems using the sums of vectors. Pupils work on several different types of real-world problems that can be modeled using triangles with three known measurements. In the process,...
Chapman University
A Pythagorean-Style Proof of the Sine Sum-of-Angles Formula
This well organized poster shows a step-by-step algebraic proof and related graphic. Understanding how formulas were derived, connects learners to the idea that the study of mathematics is continuous and cumulative. Learners will...
Curated OER
Math Handbook: Trigonometry
You'll be spinning in unit circles once you read through this jumbo-sized resource of everything you need to know about trigonometry. Each page has color-coded examples with explicit directions that detail the problems and...
Curated OER
Algebra And Trigonometry - Week 3: Law of Sines
For this law of sines worksheet, young scholars read story problems. They use both algebra and the law of sines and cosines to solve problems. This two page worksheet contains seven problems.
EngageNY
Cyclic Quadrilaterals
What does it mean for a quadrilateral to be cyclic? Mathematicians first learn what it means for a quadrilateral to be cyclic. They then investigate angle measures and area in such a quadrilateral.
Curated OER
Algebra and Trigonometry - Week 3: Story Problems
In this story problem activity, students read story problems, write equations, and solve. They use the law of sines, the law of cosines, the distance formula, and rates to solve problems. This two-page activity contains seven story...
EngageNY
Addition and Subtraction Formulas 2
Knowing the addition formulas allows for the calculations of double and half formulas. The fourth installment of 16 has the class use the addition formula to develop the double angle trigonometric formulas. Using the double formula,...
EngageNY
Addition and Subtraction Formulas 1
Show budding mathematicans how to find the sine of pi over 12. The third lesson in a series of 16 introduces the addition and subtraction formulas for trigonometric functions. Class members derive the formulas using the distance...
Curated OER
Angle Sum and Difference
In this angle sum and difference worksheet, 11th graders solve 10 different problems related to determining the angle sum and difference of numbers. First, they determine the exact value of sine and cosine degrees. Then, students utilize...
Curated OER
Trigonometry - Week 9
In this trigonometry worksheet, students use the sum-to-product formula, and the law of sines and cosines to solve trigonometry problems. This two-page worksheet contains eight problems.
Curated OER
Using the Law of Sines and the Law of Cosines to Solve Triangles
For this trigonometry worksheet, learners apply the Law of Sines and Cosines to solving for missing sides of a triangle. There are 5 questions with an answer key.
Curated OER
Algebra 2/Trigonometry Regents Exam
Learners review for the Regents Exam. In this math instructional activity, students review core concept for the Regents exam by working a variety of problems. A printable worksheet is provided.
Curated OER
Trig Review
Twelfth graders review the 6 identities of trigonometry. In this trig lesson, 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 relates to...
Curated OER
The Distance to an Unapproachable Point
Students use geometry or trigonometry to measure the distance of a far off point. They verify their measurements using a tape measure to check their work.
Curated OER
Vector Lab
Here is a math lab that helps young mathematicians understand the real-life meaning for vector addition. By building a model using spring scales and washers as weight, and then calculating the vector addition using two different methods,...
Curated OER
Triangle Inequality Theorem
Learners use the inequality theorem to solve triangles and their properties. In this geometry lesson plan, students are given spaghetti of different lengths and asked to create triangles. They conclude the necessary length needed to make...
Curated OER
The Isosceles Triangle Problem
For this geometry worksheet, 10th graders solve a problem involving an isosceles triangle. The problem appears to be deceptively easy, but instead requires the use of trigonometry to arrive at a correct solution. The one page...
Curated OER
Understanding Fundamental Trigonometric Identities
Students 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 review...
Curated OER
Magic Square Trig Identities
In this trig worksheet, 12th graders review their trig identities using a table. They answer questions 1-16 as given clues to find the answer to the correct identity.
Khan Academy
Khan Academy: Using the Trig Angle Addition Identities
Find the trig values of sums of angles whose individual trig values are known. Students receive immediate feedback and have the opportunity to try questions repeatedly, watch a video or receive hints.
Mathigon
Mathigon: Geometry: Triangles and Trigonometry: Pythagoras' Theorem
Pythagoras' Theorem: In any right-angled triangle, the square of the length of the hypotenuse (the side that lies opposite the right angle) is equal to the sum of the squares of the other two sides. (A+B=C)
Mathigon
Mathigon: Geometry: Angles and Polygons: Drawing Triangles
This lesson focuses on the Triangle Inequality, when the sum of the lengths of any two sides of a triangle is greater than the length of the third. When this happens, the three sides cannot form a triangle.
Khan Academy
Khan Academy: Find Trig Values Using Angle Addition Identities
Find the trigonometric values of various angles that (while they are not special angles) can be expressed as the sum or difference of special angles. Students receive immediate feedback and have the opportunity to try questions...
Illustrative Mathematics
Illustrative Mathematics: F Tf Sum and Difference Angle Formulas
The goal of this task is to have students derive the addition and subtraction formulas for cosine and tangent, and the subtraction formula for cosine, from the sum formula for sine. Aligns with F-TF.C.9.