Illustrative Mathematics
Finding an Unknown Angle
Teach your class how to apply their knowledge of geometry as they explore the unknown. In order to find an unknown angle, students must understand that rectangles have four interior right angles, that right angles have 90 degrees, and...
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...
CK-12 Foundation
Angles: The Angle of Discovery
Practice important angle vocabulary using an interactive lesson. As learners manipulate vertical angles, they watch the supplementary and congruent angles adjust. Questions pertaining to vocabulary and measurements follow their exploration.
CK-12 Foundation
Pythagorean Theorem for Solving Right Triangles: Solving the Triangle
Observe the change in the trigonometric ratios as angles vary. An interactive provides the values of trigonometric ratios for both acute angles in a right triangle. Pupils create a right triangle to match given criteria and find the...
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 ratios...
EngageNY
Unknown Angles
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...
EngageNY
Unknown Angle Proofs—Proofs with Constructions
Provide your emerging mathematicians with the tools to learn as they incorporate auxiliary lines to solve unknown angle proofs in this continuing segment. They decipher information from a diagram to uncover the missing pieces and...
West Contra Costa Unified School District
Law of Sines
One must obey the sine laws. A lesson plan introduces and derives the Law of Sines for non-right triangles. With examples that use the Law of Sines to determine unknown measures in triangles, the lesson plan checks to see if the Law of...
EngageNY
Solve for Unknown Angles—Angles in a Triangle
Assist your class with each angle of geometry as they use exterior angles to form linear pairs with adjacent interior angles. They cover multiple vocabulary terms and work practice problems, complete with justifications, before taking an...
Curated OER
Geometry: Lesson 8
Eighth graders engage in a lesson that is concerned with the finding of angles that are found in different two dimensional figures. They compare and contrast exterior and interior angles while also determining the unknown measures of...
Math Mammoth
Calculating Angles in a Triangle 2
In this geometry instructional activity, learners calculate unknown angles in diagrams of 3 triangles. They draw and answer short answer questions about angles. They then calculate the designated angles in 2 more diagrams.
EngageNY
Prove the Pythagorean Theorem Using Similarity
Amaze your classes with the ability to find side lengths of triangles immediately — they'll all want to know your trick! Learners use the Pythagorean Theorem and special right triangle relationships to find missing side lengths.
EngageNY
Modeling Using Similarity
How do you find the lengths of items that cannot be directly measured? The 13th installment in a series of 16 has pupils use the similarity content learned in an earlier resource to solve real-world problems. Class members determine...
Curated OER
Right Triangles
In this right triangles learning exercise, 10th graders solve and complete 5 various types of problems. First, they solve each of the triangles shown and find the area of each triangle. Then, students find the perimeter and area of the...
Curated OER
Right Triangle Trigonometry
In this trig activity, 12th graders identify the angles of a tight triangle using sine, cos and tan combined with the given sides. There are 23 problems broken down in 4 sections.
Curated OER
Geometric Properties
Students find triangular angles using the angle theorem. In this geometry instructional activity, students describe labeled triangles, use the pythagorean theorem, and rewrite information about triangles in standard form.
Curated OER
Principles of Square Roots Lesson Plan
Middle and high schoolers investigate all the different places in math that square root is present. In this geometry lesson, pupils discuss square roots as it relates to a right triangle and construction. They go over altitude, rise,...
McGraw Hill
Triangles
After reviewing characteristics of seven types of triangles, young geometers discover how to find the missing angle of a triangle. Then, they practice identifying triangles, find missing angles, and find missing side lengths of similar...
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.
Curated OER
Angles on a Line and on a Point
In this angles worksheet, students solve 24 problems pertaining to angle measurements on a line and on a point. There are also calculations of adjacent angles and supplementary angles. The page is intended as an online activity but can...
Curated OER
Parallel Lines and Types of Angles
In this angles and parallel lines worksheet, students solve 40 problems that pertain to parallel lines, supplementary, vertical, corresponding and alternate angles. There is instruction on the page with examples. This page is intended as...
Hotchalk
Triangle Sum Theorem
Your visual geometry learners will appreciate triangle drawings as they model the triangle sum theorem and algebraically solve to find the missing interior angle in a triangle. Practice problems increase in complexity and vary in their...
Curated OER
The Trig To Soccer
Students are given the background information to open the lesson: Suppose a penalty kicker in soccer could choose where he could kick from, as long as he stayed on the back line of the penalty area. Would he have a better chance of...
Curated OER
Whatcha Gunna Do When the Hulkster's Measuring Too??
Students measure using tools they have made. For this algebra lesson, students measure the height and distance using non-traditional measuring methods. They apply their findings to algebra and trigonometry properties of measurements.