RD Sharma Class 8 Chapter 15 Solutions (Understanding Shapes Polygons)

RD Sharma Class 8 Maths Solutions for Chapter 15 will help you to prepare for your CBSE exams appropriately and productively. RD Sharma Class 8 Maths Solutions for Chapter 15 discusses everything about polygons and their types. In this chapter, you will also study open and closed curves, along with some formulas to solve the questions mentioned in the exercise.

There is only one exercise in this chapter that contains 7 questions in total. These questions cover different topics of the chapter like open curves, closed curves, interior and exterior of a polygon, concave polygon, convex polygon, polygons with a different number of sides, etc and test your overall understanding of the concepts. The answers to all the questions are given by our subject matter experts for your clarity.

Instasolve is an online learning platform that provides you with easy and accurate answers. With Instasolv’s solutions to RD Sharma exercises for Class 8 Maths Chapter 15, you can study efficiently. The faculty team at Instasolv tries to explain every question step by step and makes sure that you are left with no doubts. The team of Instasolv has the expertise to help you with the solutions to the RD Sharma Class 8 Maths Problems. We provide you with comprehensive solutions to all the questions.

Important Topics for RD Sharma Class 8 Maths Solutions Chapter 15: Understanding Shapes- Polygons

Open Curves: The shapes that are not closed by any line segments are called open curves. For example, an arc of a circle can be called an open curve.

Closed Curves: The shapes that are closed by line segments are called closed curves. For instance, a circle can be called a closed curve.

Polygon: A polygon is a 2-dimensional shape formed with straight lines. Examples of the polygon are quadrilaterals, triangles, and pentagons, etc. Some of the important types of polygons are :


  • Regular polygon: In this polygon, all the sides remain equal. Also, all the interior angles are equivalent.
  • Irregular polygon: These polygons are the opposite of regular polygons. Here, the sides and angles are not equal.
  • Concave polygon: In this polygon, at least one angle measures more than 180 degrees.
  • Convex polygon: The interior angle of this polygon is less than 180 degrees. It is the opposite of a concave polygon. Also, the vertices in this polygon are always outwards.
  • Quadrilateral polygon: A quadrilateral polygon is made up of four sides. Some examples include a square, parallelogram, rectangle, etc.
  • Pentagon polygon: This polygon comprises 5 sides.



 Formulae Used in the Chapter:

  • To find the number of diagonals = 1/2 N(N-3)
  • Summation of the interior angles of the polygon = (N – 2) x 180°

Exercise Discussion for RD Sharma Class 8 Maths Solutions Chapter 15: Understanding Shapes- Polygons

  • RD Sharma Solutions for Class 8 Maths Solutions Chapter 15 contains only 1 exercise with 7 questions.
  • In question 1, you have to draw diagrams to illustrate open and closed curves.
  • In question 2, you have to classify figures as open and closed curves.
  • Question 3 asks you to draw a polygon with an interior.
  • Question 4 asks you to draw rough figures of polygons. 
  • Question 5 asks you to classify figures on the basis of different curves and polygons.
  • In question 6, you have to tell the number of diagonals in different polygons. Here, you can use the formula n(n-3)/2
  • Question 7 asks you about a regular polygon.

Benefits of RD Sharma Class 8 Maths Solutions Chapter 15: Understanding Shapes- Polygons by Instasolv

  • You can now prepare for your CBSE exams in a more simplified way with the trouble-free solutions provided by our experts for RD Sharma exercises of Chapter 15. 
  • Our subject matter experts are well-versed with the CBSE syllabus for Class 8 Maths subject and hence provide you with solutions accordingly. 
  • All our solutions are checked twice by our subject matter experts to ensure that you always receive accurate answers. 
  • These solutions will not only clear all your concepts related to this chapter but will also enable you to solve all kinds of problems that can be asked in your exams related to this chapter.