Lines of Symmetry

4th Grade MathGeometry3 pages

About this worksheet

Symmetry practice for 4th grade aimed at Common Core 4.G.3 and organized around the fold test. Four figures carry dashed candidate lines for a yes-or-no judgment: a heart cut vertically, a rectangle cut on its diagonal, an equilateral triangle cut top to base, and a letter E cut through its middle bar. Students then draw every symmetry line they can find on a square, a non-square rectangle, an equilateral triangle and a scalene triangle and record the counts. Two reasoning problems close the sheet: Maya's one successful fold and Leo's claim that a rectangle has four lines of symmetry. Answers included.

Remix for free

$Lines of Symmetry: Geometry - page 1$

$Lines of Symmetry: Geometry - page 2$

$Lines of Symmetry: Geometry - page 3$

Curriculum objectives covered

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.”

The entire sheet. Leo's diagonal claim in question 10 tests the fold definition directly, since the rectangle's diagonal fold leaves the halves hanging off each other.

What's inside this worksheet

Part 1: Is It a Line of Symmetry?

Four YES/NO items with the dashed lines drawn on: the heart and triangle lines run vertically, the rectangle's runs corner to corner, and the E's runs horizontally through the center bar.

Part 2: How Many Lines of Symmetry?

Students draw the lines themselves on a square, a non-square rectangle, an equilateral triangle and a scalene triangle, then write each total in a box.

Part 3: Symmetry Reasoning

Maya finds one fold that matches and three that fail; students state her shape's line count. Leo argues a rectangle folds four ways including both diagonals, and the explanation must use folding.

How teachers use it

Fold it for real

Cut paper rectangles before Part 1. The diagonal fold failing in their hands settles question 2 and pre-answers Leo.

Draw, do not recall

In Part 2 make students draw lines before writing counts. A written 4 for the square with only 2 lines drawn is a memorized fact, not understanding.

Common wrong answer

Expect 1 for the equilateral triangle from students who only find the vertical fold. Rotating the paper is the teachable move.

More 4th Grade Math worksheets

Multi-Digit Operations Fractions and Decimals Measurement and Data Factors and Multiples

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