* This Standard Is Part of an Additional Cluster

4.G.A.3 *This standard is part of an additional cluster

Standard 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.

Unpacked Students need experiences with figures which are symmetrical and non-symmetrical. Figures include both regular and non-regular polygons. Folding cut-out figures will help students determine whether a figure has one or more lines of symmetry.

This standard only includes line symmetry not rotational symmetry.

Example: For each figure, draw all of the lines of symmetry. What pattern do you notice? How many lines of symmetry do you think there would be for regular polygons with 9 and 11 sides. Sketch each figure and check your predictions. Polygons with an odd number of sides have lines of symmetry that go from a midpoint of a side through a vertex.

Questions to check for understanding/ increase the rigor:  How do you know that a figure is symmetrical?  Given a half of a figure and a line of symmetry, can you accurately draw the other half to create a symmetric figure?  What figure can you create that has exactly 2 lines of symmetry? 3 lines of symmetry?  How many lines of symmetry are in a regular hexagon? In a circle? (this should lead to a discussion of when there are an exact number of lines of symmetry and when there could be infinite solutions)  Think about nature, what are three examples of objects with symmetry?  In what situation is it important for things to be perfectly symmetrical?  Are all polygons symmetrical? All quadrilaterals? All triangles? Sketch examples to show symmetrical as well as non symmetrical figures.  Can you create a design that is made up of three shapes and is still symmetrical? What about with four shapes? Five shapes? (pattern blocks and tangrams can be used   Level 1 Level 2 Level 3 Level 4 Level 5 Entering Emerging Developing Expanding Bridging S Identify line- Identify line- Identify line- Identify Identify line- L symmetric symmetric symmetric line- symmetric p figures and figures and figures and symmetric figures and e e draw lines of draw lines of draw lines of figures and draw lines of v a symmetry on symmetry symmetry draw lines symmetry e them with on them, on them, of on them, k teacher answering differentiati symmetry explaining l i modeling. yes/no ng figures on them, what type of n questions that have identifying symmetry 6 with teacher lines of the type of each figure g modeling. symmetry symmetry displays. against each figure R those that has using a e don’t. word bank of a symmetry c types. h i n g ELD Standard #3: English Language Learners communicate information, ideas, and concepts necessary for academic success in the content area of Mathematics.