Introduction to Symmetry

Q. Question 3 (c)
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?

Q.

A figure is said to have line symmetry, if ____.

1. We can fold a picture in half such that the right and left halves match exactly

2. The two halves are mirror images of each other

3. The two halves are not the mirror images of each other

4. None of these

Q.

(a) Find the number of lines of symmetry of the following figure?

(b) How many angles of rotation will a regular polygon have if it has ‘n’ sides?
[4 MARKS]

Q.

A figure having no lines of symmetry is called unsymmetrical figure. Say True or False.

1. False

2. True

Q. What is a regular polygon? State the name of a regular polygon of:

ii. $4$ sides

Q.

Match the shapes mentioned in column 1 with the number of lines of symmetry it exhibits.
$$\begin{array}{cc}Shapes& \text{Lines of Symmetry}\\ \text{(a) Equilateral triangle}& \text{(i) 2}\\ \text{(b) Square}& \text{(ii) 3}\\ \text{(c) Circle}& \text{(iii) 4}\\ \text{(d) Rectangle}& \text{(iv) Infinte}\\ \text{(e) Regular Pentagon}& \text{(v) 5}\end{array}$$

1. (a)-ii, (b)-iii, (c)-iv, (d)-i, (e)-v

2. (a)-iii, (b)-ii, (c)-i, (d)-iv, (e)-v

3. (a)-ii, (b)-iii, (c)-i, (d)-iv, (e)-v

4. (a)-v, (b)-iii, (c)-iv, (d)-ii, (e)-i

Q.

Which of these puzzle pieces are symmetrical?

1. 3 & 2
2. 1 & 4
3. 3 & 4
4. All of them