Question

Which of the following exhibit linear but no rotational and point symmetry?

• A. An angle
• B. A semi-circle
• C. An equilateral triangle
• D. A scalene triangle.

Answer 1

Answer: (A), (B)

The correct options are
A

An angle

B

A semi-circle

• A figure is said to have a line of symmetry or linear symmetry if there exists a line which divides the figure into two identical halves such that they coincide when folded along this line.
• A shape has rotational symmetry when it still looks the same after a rotation of less than one full turn.
• A point symmetry occurs when a figure is generated around a single point and this point is the centre of the figure. In point symmetry, for every point on the figure, there is another point found directly to it on the other side of the centre at equal distance.

An angle has linear symmetry along its bisector but no rotational and point symmetry.

A semicircle also has only linear symmetry as shown in the figure.

An equilateral triangle has 3 lines of symmetry, point symmetry and rotational symmetry of order 3.

A scalene triangle does not have any rotational, linear or point symmetry as its sides and angles are all different.