CLASS-7
MENSURATION - PERIMETER & AREA

PERIMETER -

The perimeter is the total length of the boundary or the outer edge of a two-dimensional shape. It is the distance you would cover if you walked all the way around the shape.

In simpler terms, the perimeter is the sum of the lengths of all the sides of a figure. For example, for a rectangle, it's the sum of the lengths of all four sides, and for a circle, the perimeter is also called the circumference.

The perimeter of a shape is the total distance around the outer edge of the shape. It is calculated by summing the lengths of all its sides.

Here are formulas for the perimeter of some common shapes:

1. Square:-
         Perimeter P = 4 × side
2. Rectangle:-
         Perimeter P = 2 × (length + width)
3. Triangle:-
         Perimeter P = side 1 + side 2 + side 3
4. Circle (Circumference):-
         Perimeter P = 2 × π × radius OR P = π × diameter
5. Polygon (n-sided):-
         Perimeter P = sum of all sides

The perimeter of a closed plane figure is the total length of its boundary. The unit of perimeter is the same as that of length like cm, m etc.

·  Perimeter of a square = sum of the lengths of 4 sides (all sides are equal in a square and let each side be of length a) = 4 x a

                       Perimeter of a square (P) = 4 x a

·  Perimeter of a rectangle = sum of the lengths of all 4 sides = length + length + breadth + breadth

= 2 (length + breadth) (let l be length and b be breadth)

= 2 (l + b)

Perimeter of a rectangle (P) = 2 (l + b)

AREA -

The area of a shape is the amount of space enclosed within its boundaries. It is usually measured in square units (like square meters, square centimeters, etc.).

Here are formulas for the area of some common shapes:

1. Square:-
             Area A = side² 
2. Rectangle:-
            Area A = length × width
3. Triangle:-
            Area A = 1/2 × base × height
4. Circle:-
            Area A = π × radius²
5. Trapezoid:-
            Area A = 1/2 × (base1 + base2) × height
6. Parallelogram:-
            Area A = base × height

Each formula depends on the shape and its dimensions. Let me know if you want help with a specific area calculation!

The area of a closed plane figure is the measure of the region enclosed by its boundary.

The unit of area is square units like cm², m² etc. Also written as square centimetre, square metre etc.

·  Area of a square = (Length of a side)²          [let each side be a]

   Area of a square (A) = a²

·  Area of a rectangle = length x breadth = l x b

   Area of a rectangle (A) = l x b