Symmetry can be obtained from the balanced and proportionate similarity between two halves of an object. In simple words, one half of the figure is the mirror image of the other, and it must be understood as the concept of the line of symmetry. For instance, take a heart-shaped paper and fold it from its center. Once you are done, you can see that it gives the perfect symmetry of a heart. You can find a trace line in the heart's center where it was being folded when you unfold it. You can also witness that the centerline cut the heart into two halves. The line which cuts the heart into two parts is termed the line of symmetry.
An object or a figure that does not contain any similarity between two halves is considered an asymmetrical figure. Here, none of the halves is equal, and it can be said that asymmetrical objects have zero lines of symmetry.
It is impossible to fold the heart further to the perfect symmetry. It is because previously we had folded it along its vertical line, which gives two halves. But we cannot fold it further by doing a horizontal axis fold because the two halves will not be equal. Hence, the heart contains one line of symmetry. However, many other figures have more than one line of symmetry. Therefore, it is important to understand the points given below before learning the line of symmetry in detail.
1. An asymmetrical figure is such an object or shape that has no lines of symmetry.
2. Various objects have various numbers of lines of symmetry. For example, some have one line of symmetry, some have two lines of symmetry, a few have three, and some have more than three.
Here, a circle is a basic object that contains an infinite number of lines of symmetry. A circle is foldable at any diameter to obtain the symmetrical halves. Meanwhile, a square is another object that has multiple (4) lines of symmetry.
Some figures can be divided into two equal halves with two lines. These shapes are said to have two lines of symmetry. A rectangle is a perfect example of two lines of symmetry. It can be divided into both horizontally and vertically to get symmetric parts.
To understand the concept in detail, let us take a piece of A4 size paper followed by holding it vertically to get two halves. After doing so, fold the paper again, but this time in a horizontal position. You can observe two trace lines along with both the horizontal and vertical directions along the center. This indicates that it has two lines of symmetry.