Lesson Plan
Curated OER

Angles and Parallel Lines

For Teachers 6th
Sixth graders draw parallel and intersecting lines to observe and examine the characteristics of alternate interior angles, vertical angles, corresponding angles, and supplementary angles. Through observation, they discover the...
Lesson Plan
Curated OER

Geometry In Space

For Teachers 9th - 12th
How can we identify shapes in the Universe? High schoolers will compare and contrast elliptic and hyperbolic geometry. They will also explore one possible way to measure the curvature of the Universe, namely, by measuring the sum of the...
Lesson Plan
EngageNY

Similar Triangles in Circle-Secant (or Circle-Secant-Tangent) Diagrams

For Teachers 9th - 12th Standards
First angle measures, now segment lengths. High schoolers first measure segments formed by secants that intersect interior to a circle, secants that intersect exterior to a circle, and a secant and a tangent that intersect exterior to a...
Lesson Plan
Curated OER

Why Does ASA Work?

For Teachers 9th - 10th Standards
Your geometry learners explore Angle-Side-Angle congruence in this collaborative task. The sum of the interior angles of all triangles being one hundred eighty degrees, is the key learners will discover as they explain their reasoning...
Lesson Plan
Curated OER

Pythagorean Theorem by Graphic Manipulation

For Teachers 7th - 9th
There are many different ways to show a proof of the Pythagorean Theorem.  Here is a nice hands-on paper cutting activity that shows a graphic representation. You can even challenge your young Pythagoreans to come up with their own...
Interactive
Shodor Education Foundation

Squaring the Triangle

For Students 8th - 12th Standards
Teach budding mathematicians how to square a triangle with an interactive that shows a graphical proof of the Pythagorean Theorem. Pupils alter the lengths of the legs using sliders. Using the inputted lengths, the applet displays the...
Lesson Plan
Curated OER

Angles and Arcs

For Teachers 9th - 10th
Students discuss the sum of central angles and use string to create them on circles. They find the measure and length of both minor and major arcs. Students give examples of concentric, similar, and congruent circles and congruent arcs.
Lesson Plan
Curated OER

Properties of the Centers of a Triangle

For Teachers 9th - 12th Standards
High schoolers investigate properties of the four centers of a triangle and explore a special property of the circumcenter and orthocenter of a triangle. This instructional activity requires the use of Cabri, Jr.
Worksheet
Curated OER

Geometry Worksheet #13

For Students 10th
For this geometry worksheet #13 worksheet, 10th graders work in groups to solve 6 geometry problems, involving measurement of angles.
Lesson Plan
Curated OER

Geometry w/o Figures - Week 7 (Basic Geometry Formulas)

For Teachers 10th - 12th
In this basic geometry worksheet, students use basic formulas of geometry to find the area of a polygons, the number of sides of a polygon, and sum of the angles of various polygons. This three-page worksheet contains eight problems.
Lesson Plan
Curated OER

Lesson Exchange: Polygons (Middle, Mathematics)

For Teachers 6th - 7th
Students discover the relationship between the sides of a polygon and the number of diagonals that can be drawn from one vertex, the number of triangles that those diagonals form, and the sum of the interior angles of that polygon.
Lesson Plan
Curated OER

Intro To Quadrilaterals

For Teachers 1st - 3rd
Students engage in a lesson that is concerned with the concept of quadrilaterals and how they are used to create a rectangle for a door. They create a drawing of a quadrilateral while finding the sum of the angles. They practice problems...
Interactive
Curated OER

Angles in a Triangle

For Students 10th
In this geometry worksheet, 10th graders determine the measure or measures of the missing angle(s) in a triangle. The one page interactive worksheet contains four questions. Answers and hints are included. 
Assessment
EngageNY

Geometry Module 5: Mid-Module Assessment

For Teachers 9th - 12th Standards
How can you formally assess understanding of circle concepts? Pupils take a mid-module assessment containing five questions, each with multiple parts.
Worksheet
Curated OER

Polygons Homework

For Students 9th - 12th
In this polygons worksheet, students identify polygons that contain given parameters.  They write definitions of polygons.  Students find the measurement of exterior and interior angles of regular polygons.  This two-page...
Lesson Plan
Curated OER

Interior and Exterior Angles of Polygons

For Teachers 9th - 10th
Students identify interior and exterior angles of polygons. In this geometry lesson, students add interior and exterior angles of polygons. They use angle theorems to solve the problems.
Lesson Plan
Curated OER

Triangle Exterior Angles Theorem

For Teachers 7th - 9th
Students identify the measure of missing exterior angles. In this geometry lesson,students define and apply the exterior angle theorem to solve problems. They use Cabri software to create different angles and make investigations.
Worksheet
Curated OER

Triangle Similarity

For Students 10th
In this triangle similarity worksheet, 10th graders solve and complete 12 different problems that include defining similar and 3 similar statements using only sides and angles. First, they determine if each pair of triangles shown are...
Lesson Plan
Curated OER

Triangle Classificaition with Geometer's Sketchpad.

For Teachers 7th - 12th
Students use Geometer's Sketchpad to draw triangles and explore the classificaiton of each using the mearsures of interior angles and the lengths of the sides.
Worksheet
Curated OER

Polygon Area Review Sheet

For Students 9th - 12th
In this polygon area worksheet, learners answer 8 questions involving the area of several polygons. Students are given various details of the polygon and must find lengths of various polygons.
Printables
1
1
Houghton Mifflin Harcourt

Unit 5 Math Vocabulary Cards (Grade 6)

For Students 6th Standards
Acute angle, line of symmetry, and vertex are a few terms you'll find in a set of 90 flashcards designed to reinforce math vocabulary. Included in the set are two types of cards; a word card printed in bold font, and a...
Lesson Plan
Curated OER

Tessellation Trial and Error

For Teachers 5th - 8th
In this interactive lesson, students review attributes of equilateral polygons. They are introduced to the concept of a tessellation. Using protractors and pre-cut shapes, students arrange a variety of tiles to create tessellations. They...
Worksheet
Curated OER

Geometric Shapes and Angles

For Students 10th
In this geometry activity, 10th graders review polygons and solve for the missing angles of trapezoids and isosceles triangles. There are 10 questions on this activity with an answer key.
Lesson Plan
Curated OER

Application of Delta-Epsilon Definition of the Limit

For Teachers 12th - Higher Ed
Students create a Hexaflexagon using a formula. In this calculus lesson, students apply the definition of delta epsilon as it relates to limit to create a shape using creases. They relate the same rule to triangles and investigate angles.