Curated OER
Congruency Basics
Fourth graders investigate congruent shapes. For this congruency lesson, 4th graders explore examples of congruent shapes. Students determine how to check for congruency by sliding or flipping the shape.
EngageNY
Correspondence and Transformations
Looking for a strategy to organize the information related to transformations? The materials ask pupils to identify a sequence of rigid transformations, identify corresponding angles and sides, and write a congruence statement. They...
EngageNY
Base Angles of Isosceles Triangles
Build confidence in proofs by proving a known property. Pupils explore two approaches to proving base angles of isosceles triangles are congruent: transformations and SAS. They then apply their understanding of the proof to more complex...
EngageNY
Review of the Assumptions (part 2)
Is the amount of information getting overwhelming for your geometry classes? Use this strategy as a way to organize information. The resource provides a handout of information studied in relation to triangle congruence. It includes a...
Curated OER
Drawing Figures
Third graders draw shapes that are congruent. In this congruency lesson, 3rd graders use grid paper to draw letters and figures and their congruent partners. They complete a worksheet while working in a whole class setting with the...
Curated OER
An Application of Congruence
Students solve triangles using the properties if congruency. For this geometry lesson, students apply congruent and similar figures to solve real world and math problems. They show they are able to follow instructions.
Curated OER
Why can't We Use SSA to Prove Triangles Congruent?
Students investigate triangles and congruences. In this geometry instructional activity, students differentiate between inductive and deductive reasoning. They differentiate between similar and congruent triangles.
Willow Tree
Angles Formed by Transversals of Coplanar Lines
Create a strong understanding of the relationships formed when parallel lines intersect a transversal. Discuss each type of angle pair and their relationship to each other.
EngageNY
Reflections
Facilitate creativity in your math class as individuals learn the definition of a geometric reflection and correctly construct a model, as well as its reflected image. They use a perpendicular bisector and circles to elaborate on...
Shodor Education Foundation
Visual Patterns in Tessellations
Geometers explore the concept of tessellations. They use a tessellation applet to manipulate shapes and design their own tessellation using the applet.
EngageNY
More About Similar Triangles
Determine whether two triangles are similar. The lesson presents opportunities for pupils to find the criterion needed to show that two triangles are similar. Scholars use the definition of similarity to find any missing side...
EngageNY
Solve for Unknown Angles—Transversals
Lead your class on an exciting journey through the world of math as they review geometry facts and solve for unknown angles. They learn how to use auxiliary lines and congruent angles to correctly complete each practice problem...
EngageNY
General Prisms and Cylinders and Their Cross-Sections
So a cylinder does not have to look like a can? By expanding upon the precise definition of a rectangular prism, the lesson develops the definition of a general cylinder. Scholars continue on to develop a graphical organizer for the...
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, and...
EngageNY
Writing and Solving Linear Equations
Incorporate geometry into the solving linear equations lesson. Pupils use their knowledge of geometry to write linear equations which reinforces geometry measurement concepts while at the same time providing a familiar context for...
EngageNY
More on the Angles of a Triangle
Angles and triangles: they're all connected. Uncover the connections between angles in triangles. Scholars learn how to find both exterior and interior angle measures in triangles. The lesson emphasizes the vocabulary related to these...
EngageNY
Volumes of Familiar Solids – Cones and Cylinders
Investigate the volume of cones and cylinders. Scholars develop formulas for the volume of cones and cylinders in the 10th activity of the module. They then use their formulas to calculate volume.
EngageNY
What Lies Behind “Same Shape”?
Develop a more precise definition of similar. The lesson begins with an informal definition of similar figures and develops the need to be more precise. The class learns about dilations and uses that knowledge to arrive at a mathematical...
Curated OER
CSI Investigation of Congruence and Similarity
Students differentiate between similarity and congruence using polygons. In this geometry lesson, students label triangles based on their properties. They find missing sides and angles using the interior sum theorem.
Curated OER
Building Congruent Triangles
Students differentiate between congruent and similar triangles. In this geometry lesson, students identify the lengths and angle measures of triangles. They use postulates to prove their answers.
Curated OER
An Introductions to Congruent Polygons
Students differentiate between similar and congruent polygons. In this geometry lesson plan, students define the theorems and reasons for polygons similarity and congruence. They are given pictures and patterns to differentiate and...
Curated OER
Congruent Triangles
Tenth graders explore congruent triangles. In this geometry lesson, 10th graders investigate the conditions necessary to prove two triangles are congruent by SSS, ASA, AAS, or SAS.
Curated OER
Using Congruent Triangles
In this geometry worksheet, 10th graders use basic knowledge of congruent triangles (CPCTC) to prove that the given triangles are congruent. The one page worksheet contains four problems. Answers are not included.
Curated OER
Geometry
Fourth graders explore symmetry and congruent figures. They draw letters of the alphabet that have symmetry, draw congruent figures, draw figures on dot paper, and complete three worksheets.