Symmetry Worksheet

Symmetry is one of the first big ideas in geometry that helps children see structure in the world around them. A figure is symmetrical when a single straight line can split it into two halves that match exactly, and that line is called a line of symmetry. This symmetry worksheet gives 3rd grade students focused practice with both sides of that idea: finding every line of symmetry hiding inside a shape, and using a line of symmetry to build a matching half of their own.

This lines of symmetry worksheet moves from shapes to pictures to reasoning in three short parts. In Part A, students draw every line of symmetry on a square, a rectangle, a hexagon, and an equilateral triangle, then record how many lines they found. In Part B, they use a grid and a dashed line of symmetry to draw the missing half of two pictures so each one becomes symmetrical. In Part C, they look at a butterfly and explain in writing how a line of symmetry could prove its wings match. Print it as a math warm-up, a geometry center, a homework page, or a quick check before a unit test.

What’s Included

• 1 print-ready PDF worksheet
• Answer key
• 3 activities: drawing lines of symmetry on 4 shapes, completing 2 symmetrical grid pictures, and a written explanation

Three things make this symmetry worksheet work well for third graders. First, it asks students to draw, not just circle, so they have to test each line instead of guessing which shapes look even. Second, the grid pictures give instant feedback: a half that is drawn one square off will not match, so children learn to count carefully and check their own work. Third, the written explanation at the end pushes students past recognition and into reasoning, which is exactly the kind of thinking that geometry questions ask for later on.

Extend the lesson with a paper-folding test: cut out shapes, fold them on the lines students drew, and hold them up to the light to see whether the halves land on top of each other. Take a symmetry walk around the classroom or the neighborhood and photograph symmetrical things such as windows, leaves, letters, road signs, and faces. Try a paint-blot activity by folding paper over a drop of paint, or hand a partner half of a simple drawing and ask them to finish the other side. Letters are a fun challenge too, since some capital letters have one line of symmetry, some have two, and some have none.

Related Resources

• Seaside Symmetry Activity
• 2D and 3D Shapes Worksheet
• Identifying the Name of Shapes Worksheet
• Polygon Song by Have Fun Teaching