1. Summary

    Closed figure
    A figure with no open ends is a closed figure.

    Regular closed figures
    A closed figure in which all the sides and angles are equal.

    Perimeter
    Perimeter is the distance covered along the boundary forming a closed figure when we go round the figure once. The perimeter of a regular closed figure is equal to the sum of its sides. The concept of perimeter is widely used in real life.
    e.g.
    1) For fencing land. 
    2) For building a compound wall around a house.

    Perimeter of a rectangle
    = Length (l) + Breadth (b) + Length (l) + Breadth (b)
    = 2 ( l + b)



    Perimeter of a square
    = S + S + S + S
    = 4 × S.




    Equilateral triangle
    A triangle with all its sides and angles equal is called an equilateral triangle.
    The perimeter of an  equilateral triangle with the side 'a' = a + a + a = 3 × a

2. Videos

  • LearnNext Video

  • YouTube Video

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3. Activities & Simulations

4. Teacher Solved Exercises

6. Related Concepts

8. Contributors