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Line of Symmetry

Line of Symmetry

One-page printable reference

See It in Action

Two examples of the idea done right—and one common look-alike that is not right.

EXAMPLE

EXAMPLE

NON-EXAMPLE

Definition

A line of symmetry is a line that divides a figure into two mirror-image halves.

Key Points:

  • Each half is a reflection of the other across the line.

  • The line can be vertical, horizontal, or diagonal, depending on the figure.

  • A figure can have:

    • No lines of symmetry

    • One line of symmetry

    • Or multiple lines of symmetry

Example:

A regular triangle (equilateral) has 3 lines of symmetry. A rectangle has 2 (one vertical and one horizontal).


An equilateral with 3 lines of symmetry drawn. Each line crosses through a vertex of the triangle and passes through the midpoint of a side.
A rectangle with two lines of symmetry drawn. Each line goes through the midpoint of one side and the midpoint of the opposite side.

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This term is one piece. Our courses build it into everything around it—short videos, practice, and the “why” behind every concept.

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