Question 15 Marks
This is a picture of the new Parliament Building in Delhi.
(a) Does the outer boundary of the picture have reflection symmetry? If so, draw the lines of symmetries. How many are they?
(b) Does it have rotational symmetry around its centre?
If so, find the angles of rotational symmetry.
(a) Does the outer boundary of the picture have reflection symmetry? If so, draw the lines of symmetries. How many are they?
(b) Does it have rotational symmetry around its centre?
If so, find the angles of rotational symmetry.
Answer
View full question & answer→(a) Let us label the given figure and check whether its one side overlaps the other side when folded it about the dotted line drawn in the middle of the figure.
We observes that one half covers exactly the other half. Thus, it has a reflection symmetry.
Lines of symmetry:
There are three lines of symmetry.
(b) The given figure has rotational symmetry around its centre. When we rotate it about $120^{\circ}$, $240^{\circ}$ and $360^{\circ}$, we get the original shape. Thus, the angles of rotational symmetry are $120^{\circ}$, $240^{\circ}$ and $360^{\circ}$.
We observes that one half covers exactly the other half. Thus, it has a reflection symmetry.
Lines of symmetry:
There are three lines of symmetry.
(b) The given figure has rotational symmetry around its centre. When we rotate it about $120^{\circ}$, $240^{\circ}$ and $360^{\circ}$, we get the original shape. Thus, the angles of rotational symmetry are $120^{\circ}$, $240^{\circ}$ and $360^{\circ}$.
