Strand: GEOMETRY (4.G.)

Draw and identify lines and angles, as well as classify shapes by properties of their lines and angles (Standards 4.G.1-3)

Standard 4.G.3

Recognize a line of symmetry for a two-dimensional figure as a line across the figure such that the figure can be folded along the line into matching parts. Identify line-symmetric figures and draw lines of symmetry.

• Area Explorations
In this lesson, students will explore the area of irregular shapes to find multiple different methods for calculating area
• Finding Lines of Symmetry
The purpose of this task is for students to identify figures that have line symmetry and draw appropriate lines of symmetry.
• Geometry (4.G) - Fourth Grade Core Guide
The Utah State Board of Education (USBE) and educators around the state of Utah developed these guides for Fourth Grade Mathematics - Geometry (4.G)
• Grade 4 Mathematics Module 4: Angle Measure and Plane Figures
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.
• Grade 4 Unit 6: Geometry (Georgia Standards)
In this unit, students will draw points, lines, line segments, rays, angles (right, acute, obtuse), and perpendicular and parallel lines, identify and classify angles and identify them in two-dimensional figures, distinguish between parallel and perpendicular lines and use them in geometric figures and identify differences and similarities among two dimensional figures based on the absence or presence of characteristics such as parallel or perpendicular lines and angles of a specified size.
• Lines of symmetry for circles
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.
• Lines of symmetry for quadrilaterals
This task provides students a chance to experiment with reflections of the plane and their impact on specific types of quadrilaterals.
• Lines of symmetry for triangles
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.

http://www.uen.org - in partnership with Utah State Board of Education (USBE) and Utah System of Higher Education (USHE).  Send questions or comments to USBE Specialists - Trish  French or Molly  Basham and see the Mathematics - Elementary website. For general questions about Utah's Core Standards contact the Director - Jennifer  Throndsen.

These materials have been produced by and for the teachers of the State of Utah. Copies of these materials may be freely reproduced for teacher and classroom use. When distributing these materials, credit should be given to Utah State Board of Education. These materials may not be published, in whole or part, or in any other format, without the written permission of the Utah State Board of Education, 250 East 500 South, PO Box 144200, Salt Lake City, Utah 84114-4200.