Table of Contents
Class 7 Maths Chapter 14 Symmetry – Basics | NCERT Solutions
What is the Axis of symmetry?
Axis of symmetry is a line that divides an object into two equal halves, thereby creating a mirror-like reflection of either side of the object.
Consider an isosceles triangle. That is a triangle in which two sides are equal. A line drawn as shown below divides the triangle into two parts, such that both the parts match when they are folded along the line. This line is the axis of symmetry.
Axis of symmetry of an isosceles triangle
If the axis of symmetry is a vertical line, it is known as the Vertical axis of symmetry and when it is a horizontal line, is it known as the Horizontal axis of symmetry.
Vertical axis of symmetry Horizontal axis of symmetry
How many axes of symmetry can a shape have?
A shape can have one or more than one axis of symmetry.
We have already seen that an isosceles triangle has one axis of symmetry. Let us look at some shapes that have more than one axis of symmetry.
- A rectangle has two axes of symmetry, a horizontal axis of symmetry and vertical symmetry.
Axes of symmetry of a rectangle
Though the diagonals of a rectangle also divide it into two equal parts, they are not its axes of symmetry because if a rectangle is folded along its diagonal, the parts do not overlap exactly.
- A square has four axes of symmetry. It has a horizontal as well as a vertical axis of symmetry. Also, its two diagonals are also the axes of symmetry because when a square is folded along the diagonal, the parts overlap each other.