Lesson Plan
Curated OER

Geometry and Measurement

For Teachers 6th - 8th
Students view a right triangle displayed by the teacher. Students measure legs and the interior angles of the triangle. They look for a pattern or relationship between the legs and angles. Students use pegboards and string to create more...
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
Texas Instruments

Identifying a Triangle by its Sides and Angles

For Teachers 9th - 12th Standards
Identify triangles by their angle measures and side lengths by looking at and measuring angle measures and side lengths. Use Cabri Jr. to construct various triangles, then manipulate the construction to create the 6 types of triangles,...
Lesson Plan
Curated OER

Review of Triangles

For Teachers 8th - 10th
Students investigate the Pythagorean Theorem. For this geometry lesson, students define angles and sides of right triangles. They calculate the area and surface area using formulas derived by the Pythagorean Theorem.
Lesson Plan
Mathalicious

Been Caught Stealing

For Teachers 6th - 8th Standards
You're safe, when calculating the odds of stealing second base! Learners compare the rate of a runner to the distance the ball travels, in a lesson that explores right triangles and measurement. Full of discussion questions and fun...
Lesson Plan
Curated OER

Angles in Triangles

For Teachers 8th
Eighth graders translate word problems using mathematical ideas. In this geometry lesson, 8th graders identify angles of triangles using equations and the triangle sum theorem. They create angles with a protractor and straight edge.
Worksheet
Curated OER

Properties of Angles, Lines, and Triangles

For Students 10th
In this properties of angles, lines and triangles worksheet, 10th graders solve and complete 28 different problems that include determining the measurement of various figures shown. First, they use the geometric properties and theorems...
Interactive
Curated OER

Trigonometry Applications

For Students 10th
In this geometry worksheet, 10th graders solve application word problems involving the use or right triangle trigonometry, including angle of elevation or depression. The one page interactive worksheet contains five questions. Hints,...
Lesson Plan
Curated OER

Special Right Triangles

For Teachers 9th - 10th
Students identify different types of special right triangles. In this geometry lesson, students differentiate between right triangles and isosceles triangles. they construct the triangles using geometry software and make conjectures...
Lesson Plan
Curated OER

Triangle Side Lengths and Angles Measures

For Teachers 9th - 10th
Students identify missing sides and angles. In this geometry lesson, students use triangular theorems to identify the missing sides. They use the Pythagorean Theorem to find the different ratios of each side.
Worksheet
Curated OER

Polygons and Sketching

For Students 8th - 10th
For this geometry worksheet, learners define and draw quadrilaterals. They differentiate between the different shapes. There are 3 questions with an answer key.
Lesson Plan
Curated OER

Pyramids- Slant Height and Altitude

For Teachers 8th - 10th
Young scholars calculate the height and altitude of a pyramid. In this geometry lesson, students define the parts that make up a pyramid. They use the Pythagorean Theorem to find the missing parts of a pyramid.
Lesson Plan
Curated OER

Angle-Side Relationships

For Teachers 9th - 12th
Students calculate the different sides and angles of a triangle. In this geometry lesson, students use triangular properties to define the relationship between two triangle. They identify missing angles using the interior angle theorem.
Assessment
Inside Mathematics

Circles in Triangles

For Teachers 9th - 12th Standards
Challenge the class with inscribed circles in triangles. The assessment task requests class members use their knowledge of circles and right triangles to prove two triangles are congruent. They go on to utilize their knowledge of...
Lesson Plan
Virginia Department of Education

Special Right Triangles and Right Triangle Trigonometry

For Teachers 9th - 11th Standards
Right triangles are so special! Use special right triangles to discover the trigonometric ratios. Pairs construct special right triangles and find the values of the ratios of the sides. In the process, they discover the ratios stay the...
Lesson Plan
Curated OER

Area of Polygons

For Teachers 9th - 11th
Students engage in a lesson that is about the concept of polygons and focuses upon finding the area. They use formulas provided in the lesson in order to solve problems given by the teacher for independent practice. Geometric figures are...
Lesson Plan
Curated OER

The Truth About Triangles And Proofs

For Teachers 9th - 12th
Students engage in a lesson that is about the classification of triangles and the mathematical proofs involved in working with them. They work on a variety of problems that are created by the teacher with the focus upon the importance of...
Lesson Plan
Curated OER

Right Triangles

For Teachers 4th - 8th
Learners classify triangles and make connections regarding angle measurements and attributes of acute, right, and obtuse triangles. They listen to teacher define and explain triangles. Everyone imagines a place where a broken wing for a...
Lesson Plan
Curated OER

Polygons All Around Us!

For Teachers 9th - 12th
Students explore the concept of polygon properties. In this polygon properties lesson plan, students draw polygons with different numbers of sides such as pentagons, octagons, hexagons, etc. Students identify different geometric shapes...
Handout
Geometry Help

Geometry Help: Isosceles Triangles

For Students 9th - 10th Standards
Explains the basic concept of isosceles triangles with step-by-step instructions and methods for solving specific problems on your own relating to this topic.
Study Guide
Oswego City School District

Regents Exam Prep Center: Isosceles Triangle Theorem

For Teachers 9th - 10th
Material to supplement instruction on isosceles triangles: a lesson with related theorems and examples; an online practice quiz for students to take and check their answers; and guidelines for proving the isosceles triangle theorem.
Handout
CK-12 Foundation

Ck 12: Geometry: Triangle Relationships Study Guide

For Students 9th - 10th Standards
[Free Registration/Login may be required to access all resource tools.] This study guide reviews terminology for triangles, triangle properties, different types of triangles, and interior and exterior angle theorems.
eBook
CK-12 Foundation

Ck 12: Interactive Geometry: 4.4 Theorems About Triangles

For Students 9th - 10th Standards
Discover some theorems about triangles.
Handout
CK-12 Foundation

Ck 12: Geometry: Bisectors, Medians, Altitudes Study Guide

For Students 9th - 10th
This study guide on bisectors, medians, and altitudes covers key vocabulary, different theorems, and facts about the altitude and triangles. It is available for download with free registration.