Lines of Symmetry

Lines of symmetry are imaginary lines that divide a shape into two identical halves. When a shape has at least one line of symmetry, it means that if you were to fold the shape along that line, the two halves would perfectly overlap each other.

Types of Lines of Symmetry

There are different types of lines of symmetry:

1. Horizontal line of symmetry: A line that divides the shape into two equal parts from top to bottom.
2. Vertical line of symmetry: A line that divides the shape into two equal parts from left to right.
3. Diagonal line of symmetry: A line that divides the shape into two equal parts at an angle.

Finding Lines of Symmetry

To find the lines of symmetry of a shape, you can use the following steps:

1. Visualize: Look at the shape and imagine where a line could be drawn to create two identical halves.
2. Test: Draw a line on the shape to see if it divides it into two equal halves. If it does, that line is a line of symmetry.
3. Count: Count the total number of lines of symmetry the shape has.

Examples of Shapes with Lines of Symmetry

Here are some common shapes and their lines of symmetry:

• Circle: A circle has an infinite number of lines of symmetry, as any line passing through the center will divide it into two equal halves.
• Square: A square has 4 lines of symmetry - two vertical and two horizontal.
• Triangle: An equilateral triangle has 3 lines of symmetry - one vertical and two diagonal.
• Rectangle: A rectangle has 2 lines of symmetry - one vertical and one horizontal.

Study Guide

When studying lines of symmetry, remember to:

• Understand the concept of symmetry and how it applies to shapes.
• Practice identifying and drawing lines of symmetry for different shapes.
• Recognize the different types of lines of symmetry - horizontal, vertical, and diagonal.
• Learn the number of lines of symmetry for common shapes.

By understanding and practicing lines of symmetry, you'll develop a strong foundation in geometry and spatial reasoning.