Exercise 12.1 (Revised) - Chapter 14 - Symmetry - Ncert Solutions class 7 - Maths

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Chapter 12: Symmetry - NCERT Solutions for Class 7 Maths

Ex 12.1 Question 1.

Copy the figures with punched holes and find the axes of symmetry for the following:

Answer: 

Ex 12.1 Question 2.

Given the line(s) of symmetry, find the other hole(s): 

Answer:

Ex 12.1 Question 3.

In the following figures, the mirror line (i.e., the line of symmetry) is given as a dotted line. Complete each figure performing reflection in the dotted (mirror) line. (You might perhaps place a mirror along the dotted line and look into the mirror for the image).
Are you able to recall the name of the figure you complete?

Answer:

Ex 12.1 Question 4.

The following figures have more than one line of symmetry. Such figures are said to have multiple lines of symmetry:

Identify multiple lines of symmetry, if any, in each of the following figures:
Answer:

Ex 12.1 Question 5.

Copy the figure given here: 

Answer

figures are: 

Yes, there is more than one way.
Yes, this figure will be symmetric about both the diagonals.

Take any one diagonal as a line of symmetry and shade a few more squares to make the figure symmetric about a diagonal. Is there more than one way to do that? Will the figure be symmetric about both the diagonals?Answer: Question 6. Copy the diagram and complete each shape to be symmetric about the mirror line(s):
Ex 12.1 Question 6.

Copy the diagram and complete each shape to be symmetric about the mirror line (s) :

Answer:

Ex 12.1 Question 7.

State the number of lines of symmetry for the following figures:
(a) An equilateral triangle(b) An isosceles triangle(c) A scalene triangle
(d) A square(e) A rectangle(f) A rhombus
(g) A parallelogram(h) A quadrilateral(i) A regular hexagon
(j) A circle

Answer:

Ex 12.1 Question 8.

What letters of the English alphabet have reflectional symmetry (i.e., symmetry related to mirror reflection) about:
1. a vertical mirror
2. a horizontal mirror
3. both horizontal and vertical mirrors

Answer:

(a) Vertical mirror - A, H, I, M, O, T, U, V, W, X and $\mathrm{Y}$ mirror mirror

$\text { (b) Horizontal mirror - B, C, D, E, H, I, O and } \mathrm{X}$

(c) Both horizontal and vertical mirror $-\mathrm{H}, \mathrm{I}, \mathrm{O}$ and $\mathrm{X}$

Ex 12.1 Question 9.

Give three examples of shapes with no line of symmetry.
Answer:

The three examples are:

1. Quadrilateral
2. Scalene triangle
3. Parallelogram

Ex 12.1 Question 10.

What other name can you give to the line of symmetry of: 1. an isosceles triangle?
2. a circle?

Answer:

(a) The line of symmetry of an isosceles triangle is median or altitude.
(b) The line of symmetry of a circle is diameter.