Lesson Plan
EngageNY

Triangle Congruency Proofs (part 2)

For Teachers 9th - 10th Standards
Looking to challenge your students that have mastered basic triangle congruence proofs? A collection of proofs employ previously learned definitions, theorems, and properties. Pupils draw on their past experiences with proofs to...
Lesson Plan
EngageNY

Angle Sum of a Triangle

For Students 8th Standards
Prove the Angle Sum Theorem of a triangle using parallel line and transversal angle relationships. Pupils create a triangle from parallel lines and transversals. They find angle measures to show that the angles of a triangle must total...
Lesson Plan
EngageNY

Converse of the Pythagorean Theorem

For Students 8th Standards
Discover a new application of the Pythagorean Theorem. Learners prove and apply the converse of the Pythagorean Theorem in the 17th lesson in a 25-part series. The examples ask learners to verify right triangles using the converse...
Worksheet
Curated OER

Triangle Congruence

For Students 8th - Higher Ed
In this triangle congruence worksheet, students review 4 triangle congruence properties and 4 examples. Students are then prompted to complete 15 problems analyzing whether two triangles are congruent and determine by which property.
Lesson Plan
Curated OER

Mathematical Modeling

For Teachers 9th - 12th
Study various types of mathematical models in this math lesson. Learners calculate the slope to determine the risk in a situation described. They respond to a number of questions and analyze their statistical data. Then, they determine...
Lesson Plan
Curated OER

Investigating Trigonometric Ratios Through Similar Right Triangles

For Teachers 9th - 10th
Students identify similar and congruent right triangles. In this geometry lesson, students use trigonometric ratios to identify missing sides and angles of a triangle. They differentiate similar and congruent triangles.
Lesson Plan
Illustrative Mathematics

Running on the Football Field

For Teachers 7th - 9th Standards
Make your class into Pythagorean theorem fanatics in no time. What a great resource to get your sports enthusiasts into the math game! Read the commentary so you can you can strategize how to apply the three math practices.
Assessment
Concord Consortium

Triangles: Angle Space

For Students 9th - 12th
Three angles in a triangle, three-dimensional space, it all seems connected somehow. Given several different triangles, pupils use the three angles of the triangle as coordinates to plot points in three-dimensional space. They explore...
Worksheet
Curated OER

Measuring Angles

For Students 10th
Solve and complete 18 problems about angles. First,  demonstrate that each conjecture is false by giving a counterexample. Then write the inverse, contrapositive, and converse for the each statement. In addition, write a...
Worksheet
Curated OER

Similarity: Instructional

For Students 7th - 8th
In this similarity instructional activity, students solve and complete 7 different problems that include determining various dimensions of mirrors shown. First, they find the length of the diagonal of the large mirror in the diagram....
Worksheet
Curated OER

Identifying Triangles

For Students 5th - 7th
In this triangles practice worksheet, learners respond to 4 questions that require them to identify the pictured triangles as acute, right, or obtuse triangles.
Lesson Plan
Curated OER

Triangles

For Teachers 5th - 6th
Students draw triangles. In this shapes lesson, students discuss what they already know about triangles, what they are and what they are made up of. Students discuss the types of triangles and practice drawing each type.
Activity
Education Development Center

Similar Triangles

For Students 8th - 10th Standards
Model geometric concepts through a hands-on approach. Learners apply similar triangle relationships to solve for an unknown side length. Before they find the solution, they describe the transformation to help identify corresponding sides.
Lesson Plan
Alabama Learning Exchange

Triangle Area: No Height? Use the Sine

For Students 9th - 12th Standards
No height? No problem! Learners use their knowledge and a little help from GeoGebra to develop the Law of Sines formula. The Law of Sines helps to determine the height of triangles to calculate the area.
Interactive
CK-12 Foundation

Pythagorean Theorem and Its Converse

For Students 8th - 10th
To be a right triangle, or not to be — that is the question. Scholars drag line segments in an Internet application to see if they form right triangles. Once they get the results of the activity, they connect them to the converse of the...
Interactive
Curated OER

Angles in a Triangle

For Students 9th - 12th
In this online math worksheet, students calculate the angles in a triangle given their measurements. This excellent resource allows the students to check their answers, and to get "hints" should they run into difficulties. A terrific...
Assessment
1
1
CCSS Math Activities

Smarter Balanced Sample Items: 8th Grade Math – Target H

For Teachers 8th Standards
Pythagoras is all about being right. A presentation provides sample items for how the Pythagorean Theorem standards may show up in Smarter Balanced assessments. Seven items use the Pythagorean Theorem to find the sides of a right...
Interactive
1
1
GeoGebra

Yardwork in Segments

For Students 9th - 12th Standards
Stretch your knowledge of ratios to the coordinate plane. The interactive allows pupils to set the endpoints of a directed line segment and form a right triangle. Using rubber bands, users visualize the line segment divided into equal...
Instructional Video25:49
2
2
Flipped Math

Unit Circle and Radians

For Students 9th - 12th Standards
Measure angles is easy as pi. Pupils review special right triangles to find exact values for trigonometric functions. Scholars learn about radians and how they connect to measurements in degrees. They find exact and approximate values of...
Printables
1
1
Google

Pythagorean Theorem Foldable

For Teachers 8th - 11th Standards
Your geometry learners will enjoy this color-coded foldable that simply asks them to find the lengths of different legs and the hypotenuse of a right triangle using the Pythagorean Theorem.
Unit Plan
Radford University

The Pythagorean Theorem in Crime Scene Investigation

For Teachers 9th - 12th Standards
It's a Pythagorean who-dun-it. Pupils apply the Pythagorean Theorem in several different real-world scenarios involving right triangles. By solving each task, they find the thief who was responsible for a museum heist.
Performance
Radford University

Developing a Trigonometry Phone App

For Teachers 9th - 12th Standards
What's one more app? After reviewing how to calculate missing side lengths or angle measures in a right triangle, pupils create instructions for a phone app to do all of the tedious work. They must consider all nine cases of known...
Worksheet
Curated OER

Special Right Triangles

For Students 10th
In this right triangles learning exercise, 10th graders solve and complete 16 various types of problems. First, they find the missing side lengths in each illustration shown. Then, students place the letter of each problem on the lines...
Worksheet
Curated OER

Identifying Triangles

For Students 7th - 9th
In this triangles practice learning exercise, learners respond to 4 questions that require them to identify the pictured triangles as acute, right, obtuse, scalene, isosceles, or equilateral triangles.

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