Georgia 3.GSR.6.3
The Standard
Identify lines of symmetry in polygons.
Georgia's K-12 Mathematics Standards · Identify the attributes of polygons, including parallel segments, perpendicular segments, right angles, and symmetry.
Teacher's field guide
What This Standard Means
What Students Need to Do
- Students decide whether a polygon can be folded into matching mirror-image halves. They draw and count every line that creates those matching halves.
What Mastery Looks Like
- Students find all symmetry lines in familiar and unfamiliar polygons. They verify each choice by folding, tracing, or explaining that matching points reflect across the line.
Common Misconceptions
- Students may think any line that divides a shape into equal areas is a symmetry line. They may count a diagonal even when the two sides are not mirror images. Some assume every polygon has at least one symmetry line.
How to Assess It
- Give students a square, rectangle, scalene triangle, and regular pentagon. Ask them to draw every symmetry line and explain how folding could verify each one.
Lesson moves
Ways to Teach It
Give students paper polygon cutouts to fold, then have them trace each crease that makes both halves match exactly.
Ask students to explain why a diagonal is a symmetry line in a square but not in a non-square rectangle.
Play a sorting game where students group polygon cards by zero, one, two, or more symmetry lines.
Photograph symmetrical signs, tiles, or logos around school, then mark and count the symmetry lines on each image.
Free download
Printable 3.GSR.6.3 Worksheet
A ready-to-print activity worksheet aligned to 3.GSR.6.3, with an answer key for the teacher on its own page. No account needed.
PDF, US Letter, prints cleanly in black and white.
Download the worksheetKeep exploring
Related Standards
- 3.GSR.6.1
Identify perpendicular line segments, parallel line segments, and right angles, identify these in polygons, and solve problems involving parallel line segments,...
- 2.GSR.7.2
Identify at least one line of symmetry in everyday objects to describe each object as a whole.
- 4.GSR.8.2
Classify, compare, and contrast polygons based on lines of symmetry, the presence or absence of parallel or perpendicular line segments, or the presence or abse...
- 3.GSR.6
Identify the attributes of polygons, including parallel segments, perpendicular segments, right angles, and symmetry.
Turn this exact standard into a lesson
Grade, subject, topic, and the complete standard are prefilled. Create one free, no account needed.