Important Questions: Symmetry - Class 7 MCQ

Recall definition of line symmetry. 

All of the letters have horizontal line of symmetry since it cut them in equal parts if we draw a line in the middle of each of the letters.

Line of symmetry: It is an imaginary line that when passes through any shape or letter, divides it into two equal halves or duplicates or we can say that when a shape or a letter is folded along the line of symmetry, the figure overlaps each other.

The letters F, G, J, L, N, P, Q, R, S and Z have no line of symmetry as the letters cannot be divided into two or more equal halves such that they overlap each other.

O has many lines of symmetry.

A scalene triangle has no line of symmetry.

Since horizontal mirror is mirror along with the x-axis , so B will be seen as B

 figure 1 and figure 2 both has horizontal and vertical symmetry. So it has 2 lines of symmetry.

Rotational Symmetry is how many times a shape fits into itself when rotated.So when a circle is rotated by 90 degree it fits into its original space. So its order is 4 since it fits into itself 4 times. An equilateral triangle when rotated by 120 degrees fits into itself. So its order is 3. The 3rd shape rotates the same as the circle. So its order is 4.

Line symmetry is also known as reflection symmetry.Because a mirror line resembles the line of symmetry, where one half is the mirror image of the other half.

The second figure has only the vertical line of symmetry. So it has only 1 line of symmetry.

There are only two possibilities i.e., diagonal lines of symmetry. So there are two lines of symmetry.

The figure formed is a rhombus.

A diameter divides the circle into 2 equal parts. So, it can be considered as a line of symmetry.

Since XY=XZ and XM⊥YZ,

∠YXM=∠ZXM. So, the triangle is symmetrical about XM as it bisects the apex angle.

Rotational symmetry in capital letters describes a property in which the letter looks the same after being rotated. Capital letters that have rotational symmetry are: Z, S, H, N and O.
The letters Z, S, H and N, when rotated 180 degrees clockwise or counterclockwise, will look the same after rotation completion. This is called rotational symmetry on the order of two, because there were two 90 degree rotations. The letter O has rotational symmetry on the order of one, because after being rotated by 90 degrees, it still looks the same.