Chapter 11 of the Class 4 Maths textbook Math Mela is Fun with Symmetry. It introduces line symmetry — shapes and figures that can be divided into two identical mirror-image halves.
What Is Symmetry?
Q: What does it mean for a shape to be symmetric?
A: A shape is symmetric if it can be divided by a line (called the line of symmetry) into two halves that are exact mirror images of each other.
Lines of Symmetry
Q: How many lines of symmetry does a square have? How about a circle?
A: A square has 4 lines of symmetry (2 through the midpoints of opposite sides, 2 through opposite corners). A circle has infinite lines of symmetry, since any line through its centre divides it into two identical halves.
Symmetry in Everyday Objects
Q: Give one example of a symmetric object you see every day.
A: Examples include a butterfly’s wings, a leaf, or the human face (which is approximately symmetric).
Testing for Symmetry
Q: How can you check if a shape is symmetric using paper folding?
A: Fold the paper cut-out of the shape along the suspected line of symmetry. If both halves match up exactly on top of each other, the shape is symmetric along that line.
Frequently Asked Questions
What is a line of symmetry?
A line that divides a shape into two halves that are exact mirror images of one another.
Do all shapes have a line of symmetry?
No. Some shapes, like a scalene triangle (with all sides of different lengths), have no line of symmetry at all.
Class 4 Mathematics Chapter 11 – Notes and Extra Questions
Along with these NCERT Solutions, students can also use the Class 4 Mathematics Chapter 11 Extra Questions and Class 4 Mathematics Chapter 11 Revision Notes for quick revision and extra practice.
