+
Interactive
CK-12 Foundation

Angles of Elevation and Depression: Fly-By Calibration

For Students 9th - 12th Standards
Determine the distance between two trees from afar. Pupils use an interactive resource to create two right triangles using trees and a plane. They determine the horizontal legs of each triangle to find the distance between the two trees.
+
Lesson Plan
EngageNY

Using Trigonometry to Find Side Lengths of an Acute Triangle

For Students 9th - 10th Standards
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. 
+
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 basic...
+
Lesson Plan
Illustrative Mathematics

Two Wheels and a Belt

For Teachers 9th - 10th Standards
Geometry gets an engineering treatment in an exercise involving a belt wrapped around two wheels of different dimensions. Along with the wheels, this belt problem connects concepts of right triangles, tangent lines, arc length, and...
+
Lesson Plan
Mathematics Assessment Project

Solving Problems with Circles and Triangles

For Teachers 9th - 12th Standards
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.
+
Worksheet
Curated OER

Finding Trigonometric Ratios

For Students 11th
In this finding trigonometric ratios activity, 11th graders solve and complete 22 various types of problems. First, they find the value of each trigonometric ratio to the nearest ten-thousandth. Then, students use a calculator to find...
+
Worksheet
Curated OER

Sixteen Angle Pre-calculus Trig Problems

For Students 11th - Higher Ed
In this angle worksheet, students solve ten multiple choice and six free response questions.  These precalculus questions cover angles, radians, and right triangles.
+
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.
+
Worksheet
Curated OER

A Different Proof of the Law of Cosines

For Students 9th - 12th
In this proofs worksheet, students construct 1 proof of the law of cosines.  Students construct a right triangle within a circle to  prove the law of cosines.
+
Lesson Plan
Curated OER

Right Triangles and Unit Circles

For Teachers 9th - 11th
Students evaluate the six trigonometric values of a trig function. For 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.
+
Worksheet
Curated OER

Trigonometry Triangles

For Students 11th
In this trig worksheet, 11th graders investigate the 6 trigonometry identities and their cofunctions. They use them to solve trig problems as related to right triangles. There are 5 questions with an answer key.
+
Worksheet
Curated OER

Trigonometry

For Students 10th - 12th
In this right triangles worksheet, students use trigonometric ratios to determine the length of a side of a triangle or a missing angle measurement.  This two-page worksheet contains 20 problems.
+
Worksheet
Curated OER

Trigonometry Homework

For Students 10th - 12th
In this right angles worksheet, students use trigonometric ratios to determine the length of a missing side or a missing angle of a right triangle.  This two-page worksheet contains 19 problems.
+
Assessment
Inside Mathematics

Hopewell Geometry

For Teachers 9th - 12th Standards
The Hopewell people of the central Ohio Valley used right triangles in the construction of earthworks. Pupils use the Pythagorean Theorem to determine missing dimensions of right triangles used by the Hopewell people. The assessment task...
+
Lesson Plan
Curated OER

Geometry Exploration Basic Trig Functions

For Teachers 10th
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 formulas...
+
Worksheet
Curated OER

Easy Worksheet: Trigonometry

For Students 9th - 12th
In this trigonometry worksheet, high schoolers solve 4 short answer problems. Students find the sine, cosecant, secant or cotangent of an angle given a diagram of a right triangle with various measurements labeled.
+
Worksheet
Curated OER

Trigonometric Ratios

For Students 10th
In this trigonometric ratios worksheet, 10th graders solve 9 different problems that include determining the trigonometric ratios of each triangle. First, they determine the sides and angles of a right triangle that is shown in each...
+
Lesson Plan
Willow Tree

The Pythagorean Theorem

For Students 8th - 11th Standards
There isn't a more popular geometry formula than the Pythagorean Theorem! Learners understand the special side relationships in a right triangle. They use the Pythagorean Theorem to find missing sides and to solve problems. They begin...
+
Unit Plan
Mathematics Vision Project

Module 7: Modeling with Geometry

For Teachers 9th - 12th Standards
Model good modeling practices. Young mathematicians first learn about cross sections and solids of revolution. They then turn their attention to special right triangles and to the Laws of Sine and Cosine.
+
Worksheet
Curated OER

Tangents

For Students 9th - 12th
In this tangents worksheet, students determine the length of a missing side of a right triangles.  They use tangent lines to solve problems.  This two-page worksheet contains 11 multi-step problems.
+
Lesson Plan
Curated OER

Altitude to the Hypotenuse

For Teachers 9th - 12th Standards
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...
+
Assessment
Mathed Up!

Trigonometry

For Students 10th - 12th
Learn how to solve a triangle. Young mathematicians view a video that explains how to apply trigonometry to find missing sides and angles of a right triangle. A learning exercise tests their understanding of the concept.
+
Interactive
Curated OER

Trigonometry Formula Worksheet

For Students 10th - 12th
In this trigonometry worksheet, students solve right triangle problems.  They find the sine, cosine and tangent of given triangles.  This on-line, interactive worksheet contains 6 problems.  Answers are provided.
+
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 activity introduces the trigonometric ratios. The class discovers the relationship between the sine and cosine of complementary angles.