Texas Instruments
Copying an Angle
High schoolers will investigate geometric construction in this geometry lesson. Your pupils can explore the basic construction of copying an angle, using the constructions tools of Cabri Jr.
Virginia Department of Education
High School Mathematics Geometry Vocabulary Word Wall Cards
Having a good working knowledge of math vocabulary is especially important for geometry learners. Here are 119 pages worth of wonderfully constructed definitions, constructions, formulas, properties, theorems, and postulates. This is a...
Discovery Education
Exploring Geometry
Middle schoolers construct a three-dimensional model of a city using both similar and congruent figures and geometric transformations. City must have at least ten buildings with each building labeled and may be constructed out of paper...
Curated OER
Marshmallow Geometry
In this three-dimensional shapes geometry lesson, learners identify geometric solids and name their properties. They define "face," "edge," and "vertex," and construct geometric solids using marshmallows as vertices and toothpicks as edges.
Virginia Department of Education
Middle School Mathematics Vocabulary Word Wall Cards
Having a good working knowledge of math vocabulary is so important for learners as they progress through different levels of mathematical learning. Here is 125 pages worth of wonderfully constructed vocabulary and concept review cards....
Curated OER
Johnny Appleseed Origami
Second graders make an origami Johnny Appleseed. In this geometry lesson students follow folding instructions. They find different geometric shapes while they are folding. They create Johnny Appleseed's body and attach a face and hands...
Curated OER
Junior Architects of America
Learners create entries for the Architects of America contest, including a model of a futuristic structure, blueprints, a list of all plane and solid shapes in the structure, a persuasive argument paper that describes why the structure...
Curated OER
Why Does SAS Work?
Your geometry learners are guided by questions that help them use the language of reflections to explain the Side-Angle-Side congruence between two triangles in this collaborative task. Given a sample solution, declaring the...
EngageNY
The Volume Formula of a Pyramid and Cone
Our teacher told us the formula had one-third, but why? Using manipulatives, classmates try to explain the volume formula for a pyramid. After constructing a cube with six congruent pyramids, pupils use scaling principles from...
Curated OER
Finding the Area of an Equilateral Triangle
The problem seems simple: find the area of the equilateral triangle whose sides are each length 1. In fact, this same problem is solved in 8th grade, addressing a different Common Core standard, using the formula for area of a triangle...
Curated OER
Geometry and Measurement Pre-Test
Use this comprehensive pre-instruction assessment tool to focus your teaching where your class needs it most. Multiple choice questions assess your budding geometers' conceptual and vocabulary knowledge, but they do not solve any...
EngageNY
Dilations from Different Centers
Can you follow a composition of transformations, or better yet construct them? Young mathematicians analyze the composition of dilations, examining both the scale factor and centers of dilations. They discover relationships for both...
EngageNY
Circles, Chords, Diameters, and Their Relationships
A diameter is the longest chord possible, but that's not the only relationship between chords and diameters! Young geometry pupils construct perpendicular bisectors of chords to develop a conjecture about the relationships between chords...
EngageNY
Modeling with Polynomials—An Introduction (part 1)
Maximizing resources is essential to productivity. Class members complete an activity to show how math can help in the process. Using a piece of construction paper, learners construct a box with the maximum volume. Ultimately, they...
EngageNY
Rotations
Searching for a detailed lesson to assist in describing rotations while keeping the class attentive? Individuals manipulate rotations in this application-based lesson depending on each parameter. They construct models depending on the...
EngageNY
Tangent Segments
What's so special about tangents? Learners first explore how if a circle is tangent to both rays of an angle, then its center is on the angle bisector. They then complete a set of exercises designed to explore further properties and...
Illustrative Mathematics
Points equidistant from two points in the plane
Young geometers apply their deductive reasoning skills and knowledge of proving triangles congruent in a task that asks them to prove if a point lies on the perpendicular bisector of a segment, then it is equidistant from the endpoints...
Illustrative Mathematics
Similar Triangles
Proving triangles are similar is often an exercise in applying one of the many theorems young geometers memorize, like the AA similarity criteria. But proving that the criteria themselves are valid from basic principles is a great...
EngageNY
Properties of Tangents
You know about the tangent function, but what are tangent lines to a circle? Learners investigate properties of tangents through constructions. They determine that tangents are perpendicular to the radius at the point of tangency,...
Inside Mathematics
Hopewell Geometry
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...
NY Learns
Investigation - Looking at Polygons
Middle schoolers construct polygons by plotting points on a coordinate plane. Pupils connect the points and identify which polygons they have drawn. They will need graph paper to carry out the assigned activities. A vocabulary list,...
Curated OER
Math: Shapes and More Shapes
Students locate lines of symmetry in regular polygons and predict the number of lines of symmetry in an octagon. In three different polygons, they construct all lines of symmetry and after making their prediction about the octagon,...
Curated OER
Lines of Symmetry
Fourth graders identify lines of symmetry using reflections and then construct figures that have one or more lines of symmetry. In this symmetry lesson plan, 4th graders use sets of shapes, pattern blocks, a mirror, and more.
Curated OER
Triangles Congruency Theorems
Tenth graders investigate the theorems of ASA, AAS, AAA and ASA. In this geometry lesson, 10th graders discuss the theorems of triangles and how it is used to solve for missing sides or angles. They review how two angles are formed by...