Line of Symmetry
Concept
In Geometry, a figure is said to be symmetrical when it is divided into two identical halves with the help of a line. These lines are called the lines of symmetry of a shape or figure and a line of symmetry always cuts the shape into two equal and similar parts. The word “Symmetry” comes from the Greek word which implies “to measure together”.
Rules
A line of symmetry divides a shape or an object into two regions that are mirror images of each other across the line.
1. To draw a line of symmetry, look for two halves of the shape or object that are mirror images of each other. Then, draw the line of symmetry between these halves.
2. The right half of the shape or object is the mirror image of the left half. So, the line that passes through the middle is a line of symmetry.
Example
Is the dotted line a line of symmetry?
Solution
Yes the dotted line is a line of symmetry as the right half of the object is the mirror image of the left half. So, the line that passes through the middle is a line of symmetry.
Practice Line of Symmetry
Practice Problem 1
Is the dotted line a line of symmetry?
Practice Problem 2
Does this picture have line symmetry?
Practice Problem 3
Which picture has line symmetry?
Practice Problem 4
Which picture has line symmetry?
The line of symmetry is an imaginary line or axis that passes through the center of any picture, shape or object and it is divided into two identical halves.