EngageNY
Congruence, Proof, and Constructions
This amazingly extensive unit covers a wealth of geometric ground, ranging from constructions to angle properties, triangle theorems, rigid transformations, and fundamentals of formal proofs. Each of the almost-forty lessons is broken...
Curated OER
Partitioning a Hexagon
The task at hand is to partition a hexagon into two, four, and eight congruent figures. Make sure to give your wizards a sheet of triangle grid paper on which to decompose the hexagons. Have them explain which rotations, reflections, or...
Curated OER
Escher-Esque Tessellations
Middle and high schoolers participate in a seven-part lesson creating Escher-Esque tessellations. They demonstrate their knowledge of geometric transformations after viewing a PowerPoint presentation, conducting Internet research, and...
Curated OER
Visualizing and Naming Polygons
A really useful resource contains 116 slides covering basic geometric concepts related to 2-D or plane shapes. Shape properties, translations, reflections, congruence, symmetry, and grid work are all laid out in a comprehensive and...
Flipped Math
Chords and Arcs
Congruence breeds congruence. Pupils learn three more circle theorems dealing with congruent chords and arcs. Learners use the theorems to find the measures of chords and arcs in circles by applying previously learned concepts in the...
Radford University
Triangles in Parallelograms
What's the point of looking at triangles when trying to draw parallelograms? Given three non-collinear points, pupils determine and justify all possible points that would create a parallelogram. They then analyze the four triangles that...
PBS
Accessible Shapes
All the 2-D and 3-D measurement work you need is in one location. Divided into three sections, the geometry lesson plans consist of visualization of three dimensions, classifying geometric figures, and finding surface area and volume....
CCSS Math Activities
Smarter Balanced Sample Items: 8th Grade Math – Claim 3
Communication is the key. A dozen sample items require scholars to communicate their reasoning involved in arriving at a solution. The PowerPoint from the Gr. 8 Claim 2 - 4 Item Slide Shows series uses a variety of content to illicit...
CCSS Math Activities
Smarter Balanced Sample Items: 8th Grade Math – Target G
Transform the thinking of transformations with six sample items that illustrate the first four standards in the eighth grade geometry domain. Items use the coordinate plane to transform figures and analyze the relationship of the figures...
Mathematics Vision Project
Module 2: Congruence, Construction and Proof
Construct yourself a winning geometry unit. A set of lessons introduces geometry scholars to constructions and proofs with compasses and straightedges. It also covers triangle congruence through transformations. This is the second of...
101 Questions
Best Reflection
Which is the best reflection of them all? Given four diagrams, pupils determine which one shows the most accurate reflection of a quadrilateral. Two images provide the distances of each vertex from the line of reflection, as well as the...
GeoGebra
Conjectures and Proof
Transform proofs using triangle rotations. By rotating a triangle around various points, class members develop proofs. Participants prove relationships of alternative interior angles formed by parallel lines and the sum of the interior...
CK-12 Foundation
Properties of Congruence: Congruent Figures
No two resources are exactly the same, but polygons can be. Scholars match congruent figures by dragging them together in an interactive. They answer some challenge questions that justify their matches.
CK-12 Foundation
Properties of Congruence: Polygon Party
Don't let congruent figures drag you down. Young mathematicians use an interactive to drag figures onto one another to determine if the figures are congruent.
Mathematics Vision Project
Transformations and Symmetry
Flip, turn, and slide about the coordinate plane. Pupils define the rigid motions and experiment with them before determining the relationships of the slopes of parallel and perpendicular lines. The sixth unit in a nine-part series...
Virginia Department of Education
Side to Side
Congruent figures: two figures that want to be just like each other. Individuals learn to distinguish between figures that are congruent and those that are not. Measuring the lengths of line segments and angles helps in this endeavor.
Virginia Department of Education
Similar Figures
How similar do figures have to be to be similar figures? Individuals learn to identify similar figures by verifying that angles are congruent and sides are proportional. Additionally, they match the corresponding parts of similar figures.
Mathematics Vision Project
Congruence, Construction and Proof
Learn about constructing figures, proofs, and transformations. The seventh unit in a course of nine makes the connections between geometric constructions, congruence, and proofs. Scholars learn to construct special quadrilaterals,...
Noyce Foundation
Part and Whole
Now you'll never have trouble cutting a cake evenly again. Here is a set of five problems all about partitioning shapes into a given number of pieces and identifying the fractional amount of each piece. As learners progress through the...
Noyce Foundation
Lyle's Triangles
Try five problems on triangles. Levels A and B focus on shapes that can be created from right triangles. Level C touches upon the relationship between the area of a six-pointed star and the area of each triangle of which it is composed....
Virginia Department of Education
Congruent Triangles
Is this enough to show the two triangles are congruent? Small groups work through different combinations of constructing triangles from congruent parts to determine which combinations create only congruent triangles. Participants use the...
EngageNY
End-of-Module Assessment Task - Grade 8 Mathematics (Module 2)
Can your classes apply the knowledge they have learned? Use this performance task to find out! Individuals use transformations to explain congruence and angle relationships within parallel lines to find missing values. They show what...
EngageNY
Definition of Congruence and Some Basic Properties
Build a definition of congruence from an understanding of rigid transformations. The lesson asks pupils to explain congruence through a series of transformations. Properties of congruence emerge as they make comparisons to these...
EngageNY
Why Move Things Around?
Explore rigid motion transformations using transparency paper. Learners examine a series of figures and describe the transformations used to create the series. They then use transparency paper to verify their conclusions.