Question 9
Copy the following on a dot grid. For each figure draw two more lines to make a shape that has a line of symmetry.

- A shape has a line of symmetry (mirror line) if folding it along that line makes the two halves match exactly.
- To complete each figure using exactly two more lines, identify the intended line of symmetry (horizontal or vertical) and plot points at equal distances on the opposite side of that line on the dot grid.
Step 1 · Complete Figure 1 (Top Left)
The original bent line is completed by adding two lines to form a symmetric pentagon.
- Vertices of the completed shape: , , , , and
- Line of symmetry: Horizontal line passing through
- Points and are reflections of each other across .
- Points and are reflections of each other across .
- Point lies on the line of symmetry.
Step 2 · Complete Figure 2 (Top Middle)
The original L-shaped line is completed by adding two lines to form a symmetric hexagon.
- Vertices of the completed shape: , , , , , and
- Line of symmetry: Vertical line passing through
- Points and are reflections of each other across .
- Points and are reflections of each other across .
Step 3 · Complete Figure 3 (Top Right)
The original figure is completed by adding two lines to form a symmetric octagon.
- Vertices of the completed shape: , , , , , , , and
- The shape is completed symmetrically as shown in the diagram.
Step 4 · Complete Figure 4 (Bottom Left)
The original U-shaped figure is completed by adding two lines to form a rectangle.
- Vertices of the completed shape: , , , and
- Lines of symmetry:
- Horizontal line passing through
- Vertical line passing through
Step 5 · Complete Figure 5 (Bottom Middle)
The original V-shaped figure is completed by adding two lines to form a kite.
- Vertices of the completed shape: , , , and
- Line of symmetry: Horizontal line passing through
- Points and are reflections of each other across .
- Points and lie directly on the line of symmetry.
Step 6 · Complete Figure 6 (Bottom Right)
The original shape is completed by adding two lines to form a symmetric hexagon.
- Vertices of the completed shape: , , , , , and
- Line of symmetry: Horizontal line passing through
- Points and are reflections across .
- Points and are reflections across .
- Point lies on the line of symmetry.
Each figure is completed on the dot grid using two additional lines to create a shape with a line of symmetry, as illustrated in the diagrams.
- Miscounting Dot Distances: Placing the reflected vertex at an unequal distance from the axis of symmetry breaks the mirror property.
- Choosing the Wrong Axis: Attempting to force a vertical line of symmetry on figures whose given lines are naturally symmetric across a horizontal line.
More questions in FIO
Do you see any line of symmetry in the figures at the start of the chapter? What about in the picture of the cloud?
For each of the following figures, identify the line(s) of symmetry if it exists.
Punching Game
The fold is a line of symmetry. Punch holes at different locations of a folded square sheet of paper using a punching machine and create different symmetric patterns.
In each of the following figures, a hole was punched in a folded square sheet of paper and then the paper was unfolded. Identify the line along which the paper was folded. Figure (d) was created by punching a single hole. How was the paper folded?
Given the line(s) of symmetry, find the other hole(s):
Here are some questions on paper cutting. Consider a vertical fold. We represent it this way:
Vertical Fold
Similarly, a horizontal fold is represented as follows:
Horizontal Fold
After each of the following cuts, predict the shape of the hole when the paper is opened. After you have made your prediction, make the cutouts and verify your answer.
Trace each figure and draw the lines of symmetry, if any:
Copy the following on a dot grid. For each figure draw two more lines to make a shape that has a line of symmetry.
Find the angles of symmetry for the given figures about the point marked •.
(a) (b) (c)
Which of the following figures have more than one angle of symmetry?
Give the order of rotational symmetry for each figure:
Colour the sectors of the circle below so that the figure has:
(i) 3 angles of symmetry
(ii) 4 angles of symmetry
(iii) What are the possible numbers of angles of symmetry you can obtain by colouring the sectors in different ways?
Draw two figures other than a circle and a square that have both reflection symmetry and rotational symmetry.
Draw, wherever possible, a rough sketch of:
a. A triangle with at least two lines of symmetry and at least two angles of symmetry.
b. A triangle with only one line of symmetry but not having rotational symmetry.
c. A quadrilateral with rotational symmetry but no reflection symmetry.
d. A quadrilateral with reflection symmetry but not having rotational symmetry.
In a figure, is the smallest angle of symmetry. What are the other angles of symmetry of this figure?
In a figure, is an angle of symmetry. The figure has two angles of symmetry less than . What is its smallest angle of symmetry?
Can we have a figure with rotational symmetry whose smallest angle of symmetry is:
a. ?
b. ?