# RD Sharma Solutions for Class 7 Maths Chapter 18: Symmetry

In this chapter, all the symmetry-related concepts and topics are taught to the students. Firstly, before diving into the topic, one should understand the term symmetry. Symmetry is nothing but a balanced and proportionate similarity found in two halves of an object. It indicates that one-half is the mirror image of the other half.

In RD Sharma Solutions for Class 7 Maths Chapter 18 symmetry, students study various concepts under the topic of lines of symmetry. They are; lines of symmetry, lines of symmetry of a line segment, lines of symmetry of an angle, lines of symmetry of an isosceles triangle, lines of symmetry of a rhombus, lines of symmetry of rectangle, lines of symmetry of an isosceles trapezium, lines of symmetry of a kite, lines of symmetry of a circle, lines of symmetry of an arrowhead and lines of symmetry of a semicircle.

On top of that, students are also taught a concept like the line of symmetry of some regular polygons, where under that topic, there are many important concepts. For example, they are; lines of symmetry of a square, lines of symmetry of an equilateral triangle, lines of symmetry of a regular hexagon, and lines of symmetry of a regular pentagon. Other than this, a new concept called reflection is also taught. It is considered as a kind of symmetry which is for reflections. Hence, it is sometimes referred to as mirror symmetry. Furthermore, rotational symmetry has also been discussed in the chapter. In rotational symmetry, a shape can be rotated on its axis, and after the rotation, it looks the same. The rotation angle measures how the figure is being rotated about a specific point called the point of rotation. Finally, the details of rotational symmetry are also explained.