NCERT MCQ Solutions for Class 4 Maths Mela Chapter 11 Fun with Symmetry

Chapter 11 titled “Fun with Symmetry” explores various concepts related to symmetry in designs, shapes and patterns. All activities in the chapter focus on understanding symmetrical patterns, lines of symmetry, and creating symmetrical designs.

In the ink design activity, the symmetrical pattern is created by folding a sheet of paper in half, sprinkling drops of water colors in the center of the fold, pressing it to spread the color evenly and then opening it to reveal a symmetrical design.

The chapter asks students to try making and flying both symmetrical and asymmetrical paper airplanes. Symmetry is important because it creates equal weight distribution and balance on both sides, which helps the airplane fly properly and for a longer time.

A square has 4 lines of symmetry – two that connect the midpoints of opposite sides and two that connect opposite corners (diagonals).

When reflected vertically in a mirror, the digit 8 looks exactly the same as its original form, maintaining its symmetry. Other digits like 1, 3 or 7 would appear different when reflected.

Letters on ambulances are written in reverse so that when drivers see the ambulance in their rear-view mirrors, the text appears correctly readable, enabling them to recognize it’s an ambulance and give way.

When you cut a folded paper along a line parallel to the fold, the cut appears symmetrically on both sides of the fold line when the paper is unfolded, creating a symmetrical pattern.

In the “catty wall” activity, after cutting the outline of the cat’s head and ears, the top piece is slid down to align with the larger piece. This sliding (translation) transformation helps create tiles that fit perfectly without gaps or overlaps.

The main property of tiling patterns, as emphasized in the chapter, is that they must fit together without gaps or overlaps to create a continuous pattern that can cover a surface completely.

The number 808 would look the same when reflected in a vertical mirror because both 8s are symmetrical and 0 is also symmetrical. The digits maintain their appearance when reflected vertically.

To create a symmetrical pattern with folded paper and scissors, you need to cut shapes that are placed symmetrically relative to the fold line. This ensures that when unfolded, the pattern will be symmetrical along the fold line which acts as the line of symmetry.

An isosceles triangle has exactly one line of symmetry that passes through the vertex with the unique angle and bisects the opposite side. A square has 4 lines of symmetry, a circle has infinite lines of symmetry and a regular pentagon has 5 lines of symmetry.

When you fold a paper once and make two cuts in the middle, upon opening, each cut creates two sides on the original shape. Starting with a rectangular paper (4 sides), plus 2 additional sides created by the cuts, results in a shape with 6 sides.

The purpose of the “nature walk” activity is to observe patterns, designs and symmetry in nature. Students are asked to collect leaves and flowers, categorize them as symmetrical or non-symmetrical and use them to create designs and patterns.

The sliding, flipping, and rotating as transformations used in creating tiling patterns, but stretching (changing the size or proportions) is not mentioned as one of the transformations.