Page 220 - ICSE Math 6

THINK SMART

1. Name the regular polygon having 6 lines of symmetry.

2. Move any two sticks to obtain a symmetric figure.

3. Can an obtuse-angled triangle have two or more lines of symmetry?

Individual Activity

Objective: To find line(s) of symmetry of a circle, rectangle and a square

Material required: White sheets of paper, a pencil and a pair of scissors

1. Finding line(s) of symmetry of a circle

Step 1: Draw a circle on a white sheet of paper.
Step 2: Cut this circle using a pair of scissors.

Step 3: Fold the circle in such a way that the crease
passes through the centre of the circle.

Step 4: We observe that each half part of the circle overlaps the other completely. Therefore,
on unfolding the crease so formed we get a line of symmetry.
Step 5: Now, keep folding the circle again and again along different lines.

Step 6: Everytime we obtain a new line of symmetry passing through the
centre.

Step 7: Therefore, it is clear that a circle has infinite lines of symmetry.

2. Finding line(s) of symmetry of a rectangle

Step 1: Draw a rectangle on a white sheet of paper.
Cut it using a pair of scissors.

Step 2: Now fold it along a vertical line in such a way
that the two parts of the rectangle coincide with
each other.

204