Perimeter, Area and Volume - Perimeter of Square and Rectangle

Perimeter is defined as the total length of the boundary of a closed two-dimensional figure. Visually, imagine placing a string exactly along the outer edges of a shape; the total length of that string when straightened out is the perimeter.

A Rectangle is a four-sided shape where opposite sides are equal and all four corners are right angles ($90^{\circ}$). Visually, it consists of two longer horizontal sides called Length ($l$) and two shorter vertical sides called Breadth ($b$).

The Perimeter of a Rectangle is the sum of all its four sides ($l + b + l + b$). Because the opposite sides are identical, we can simplify this calculation by adding one length and one breadth together, then multiplying the sum by 2.

A Square is a special type of rectangle where all four sides are of equal length. Visually, it is a perfectly symmetrical shape where every side ($s$) is the same, and all internal angles are right angles.

The Perimeter of a Square is found by adding the lengths of all four equal sides ($s + s + s + s$). Instead of repeated addition, we calculate it by multiplying the length of one side by 4.

Standard units of perimeter are linear units such as centimeters ($cm$), meters ($m$), millimeters ($mm$), or kilometers ($km$). It is essential to ensure that all side measurements are converted to the same unit before performing any calculations.

When solving for missing dimensions, we can use the perimeter in reverse. For a square, dividing the perimeter by 4 gives the side length. For a rectangle, dividing the perimeter by 2 gives the sum of one length and one breadth ($l + b$).