Line symmetry & rotational symmetry | Symmetry | Assessment | English | Grade 7

Which of the following letters has no line of symmetry and has the order of rotation 1?

• R

• Z

• S

• B

Answer explanation

The vertical and horizontal lines do not divide the letter R into two equal parts. So letter R has no line of symmetry. When letter R is rotated by 360⁰ after that only the exact letter R is obtained. Hence the order of rotation of letter R is 1. The letter Z and letter S has no line of symmetry but has the order of rotation as 2. The letter B has 1 line of symmetry and order of rotation is 1. Hence option 1 is the right answer.

Tags

CCSS.HSG.CO.A.4

Which of the following statements is true? (i) The given figure has 3 lines of symmetry. (ii) The order of rotation of the given figure is 3.

• Only statement (i)

• Only statement (ii)

• Both statement (i) and statement (ii)

• Neither statement (i) nor statement (ii)

Answer explanation

The given figure is of an equilateral triangle. It has 3 lines of symmetry as shown in the adjoining figure. Hence, statement (i) is true. When an equilateral triangle is rotated by an angle of 120⁰, 240⁰ and 360⁰, we get the original triangle. Therefore, order of rotation of the given figure is 3. Hence statement (ii) is also true. So, option 3 is the right answer.

Tags

CCSS.HSG.CO.A.4

Which of the following options is true with respect to the given figure?

• The figure has 1 line of symmetry and the order of rotation is 1

• The figure has 2 lines of symmetry and the order of rotation is 2

• The figure has 3 lines of symmetry and the order of rotation is 3

• The figure has 4 lines of symmetry and the order of rotation is 4

Answer explanation

In the given figure, the vertical line, horizontal line, and both the slanted lines are lines of symmetry which divide the figure into two equal parts. Therefore the figure has 4 lines of symmetry. When the given figure is rotated by an angle of 90⁰, 180⁰, 270⁰ and 360⁰- in each case the figure looks exactly the same as the original figure. Hence the order of rotation of the given figure is 4 Therefore, option 4 is the required answer.

Tags

CCSS.HSG.CO.A.4