This is a task from the Illustrative Mathematics website that is one part of a complete illustration of the standard to which it is aligned. Each task has at least one solution and some commentary that addresses important asects of the task and its potential use. Here are the first few lines of the commentary for this task: Each shape below has a line of symmetry. Draw a line of symmetry for each shape. Not every shape has an line of symmetry. Which of the four shapes belo...

This 3 lesson instructional unit helps students investigate many different aspects of triangles including basic properties of triangles, building other shapes from triangles, the dependence of the third side length on the other two (Triangle Inequality Theorem), and the Sierpinski Triangle fractal. The lesson includes student activity sheets and links to interactive applets.

In this activity, learners use pattern blocks and mirrors to explore symmetry. Learners work in pairs and build mirror images of each other's designs. In doing so, learners will examine principles of symmetry and reflection.

This is a 4th grade unit interview assessment for geometry.  Instead of giving a "standardized assessment", this is an interview that covers all of the 4th grade geometry standards.  You as a teacher have a chance to see each individual student work through problems and have them explain their thinking.  It is extremely easy to spot where their deficiencies are and be able to give them extra help in those areas.

This google slide show is to be used as a routine in grade 4 during the third quarter. Students will be given time to notice and wonder about each slide, with their thinking guided toward geometry. Discussions will promote precise geometry vocabulary and connections between images.

This 20-day module introduces points, lines, line segments, rays, and angles, as well as the relationships between them. Students construct, recognize, and define these geometric objects before using their new knowledge and understanding to classify figures and solve problems. With angle measure playing a key role in their work throughout the module, students learn how to create and measure angles, as well as create and solve equations to find unknown angle measures. In these problems, where the unknown angle is represented by a letter, students explore both measuring the unknown angle with a protractor and reasoning through the solving of an equation. Through decomposition and composition activities as well as an exploration of symmetry, students recognize specific attributes present in two-dimensional figures. They further develop their understanding of these attributes as they classify two-dimensional figures based on them.

Find the rest of the EngageNY Mathematics resources at https://archive.org/details/engageny-mathematics.

In this lesson students are introduced to various types of symmetry. After exploring the symmetries that exist with letters of the alphabet, they make inversions of their own name. Suggestions for implementation and support materials are provided.

This is an instructional task that gives students a chance to reason about lines of symmetry and discover that a circle has an an infinite number of lines of symmetry. Even though the concept of an infinite number of lines is fairly abstract, fourth graders can understand infinity in an informal way.

This task provides students a chance to experiment with reflections of the plane and their impact on specific types of quadrilaterals. It is both interesting and important that these types of quadrilaterals can be distinguished by their lines of symmetry.

This task is intended for instruction, providing the students with a chance to experiment with physical models of triangles, gaining spatial intuition by executing reflections.

(Nota: Esta es una traducción de un recurso educativo abierto creado por el Departamento de Educación del Estado de Nueva York (NYSED) como parte del proyecto "EngageNY" en 2013. Aunque el recurso real fue traducido por personas, la siguiente descripción se tradujo del inglés original usando Google Translate para ayudar a los usuarios potenciales a decidir si se adapta a sus necesidades y puede contener errores gramaticales o lingüísticos. La descripción original en inglés también se proporciona a continuación.)

Este módulo de 20 días introduce puntos, líneas, segmentos de línea, rayos y ángulos, así como las relaciones entre ellos. Los estudiantes construyen, reconocen y definen estos objetos geométricos antes de usar su nuevo conocimiento y comprensión para clasificar las cifras y resolver problemas. Con la medida de ángulo que juega un papel clave en su trabajo a lo largo del módulo, los estudiantes aprenden cómo crear y medir ángulos, así como crear y resolver ecuaciones para encontrar medidas de ángulo desconocidas. En estos problemas, donde el ángulo desconocido está representado por una letra, los estudiantes exploran ambos midiendo el ángulo desconocido con un protractor y razonamiento a través de la resolución de una ecuación. A través de actividades de descomposición y composición, así como una exploración de la simetría, los estudiantes reconocen atributos específicos presentes en figuras bidimensionales. Desarrollan su comprensión de estos atributos a medida que clasifican las figuras bidimensionales basadas en ellas.

Encuentre el resto de los recursos matemáticos de Engageny en https://archive.org/details/engageny-mathematics.

English Description:
This 20-day module introduces points, lines, line segments, rays, and angles, as well as the relationships between them. Students construct, recognize, and define these geometric objects before using their new knowledge and understanding to classify figures and solve problems. With angle measure playing a key role in their work throughout the module, students learn how to create and measure angles, as well as create and solve equations to find unknown angle measures. In these problems, where the unknown angle is represented by a letter, students explore both measuring the unknown angle with a protractor and reasoning through the solving of an equation. Through decomposition and composition activities as well as an exploration of symmetry, students recognize specific attributes present in two-dimensional figures. They further develop their understanding of these attributes as they classify two-dimensional figures based on them.

Find the rest of the EngageNY Mathematics resources at https://archive.org/details/engageny-mathematics.