Perimeter

Perimeter

Any shape that lies on a flat surface and has only two dimensions i.e. length and breadth are called 2-D (two-dimensional) shape. Every polygon is a 2-D figure which lies flat on a plane. Polygons are closed figures which are bounded by a chain of line segments, for example, triangles, rectangles, and squares. Perimeter (peri: around; meter: measure) of a polygon is the distance or linear measure of these bounded line segments. In other words, it is the length of its boundaries. Its unit is centimetre (cm) or meter (m).

Consider a rectangle, the surrounding distance indicated by the arrows form the perimeter of the given rectangle. It is the sum total covered by two lengths and two breadths.

Perimeter of Different Shapes – Formulas

We know every shape is different from one another. Thus, the formula for perimeters of geometric shapes also varies from one shape to another. Some common shapes and formula for finding their perimeters are as follows.

Perimeter of Rectangle

Rectangle is a four-sided polygon having two dimensions i.e. length and breadth.

Perimeter of a rectangle = sum of four sides

= AB     +     BC        + CD       +   AD

= length + breadth + length + breadth

= 2 length + 2 breadth

Perimeter of a rectangle =   2 × (length + breadth)

Perimeter of Circle

Circle is a collection of points and perimeter of a circle is known as circumference of a circle.

Circumference of a circle:-

Where r is the radius of the circle and

Perimeter of Square

Square is also a polygon where all its sides are the same.

The perimeter of a square = sum of all four sides

= a + a + a+ a

= 4a

The perimeter of a square = 4 side