In geometry, perimeter can be defined as the path or the boundary that surrounds a plane shape. The word perimeter has been derived from the Greek word “peri” meaning around and “metron” which means measure. Measurement of length is applicable in many real-life situations. For example, farmers have to fence their fields to protect their crops from animals. The required length of the fence can be calculated accurately if one is familiar with the concept of perimeter. In this sub-topic, you will discuss the length and properties of the plane geometrical figures and you Perimeter is the distance around the edge of a plane shapes. The perimeter of all plane shapes can be determined by adding the lengths of their sides.

Triangle

Recall that triangle is a three-sided polygon and it can be classified into different types based on the measure of its sides and angles. The perimeter of a triangle is defined as the total length of its boundary.

In general, the perimeter of a triangle with length of sides a, b and c units is given by the formula:

P = a + b + c.

Rectangle

Rectangles are four-sided polygons. The perimeter of a rectangle is the sum of the length of its sides. Hence, we can find the perimeter of a rectangle by adding the lengths of all four sides of a rectangle.

Since opposite sides of a rectangle are always equal, we need to find the dimensions of only two sides to find the perimeter of a rectangle. Thus, the perimeter of a rectangle with length and width is twice of the sum of length and width.

In general, the perimeter (P) of a rectangle whose length is ℓ and width is ω is given by the formula:

P = 2 × (ℓ+ ω).

Square

A square is a type of rectangle in which the adjacent sides are equal. In other words, all sides of a square are equal.

The perimeter of a square is the total length of all sides of the square. Hence, we can find the perimeter of a square by adding all its sides. That is, perimeter

(P) = s + s + s + s = 4s units.

The perimeter of a square whose side length is s units is 4 times the length of its side.

In general, the perimeter of a square whose side length is s is given by the formula:

P = 4s

Parallelogram

Recall that a quadrilateral (four-sided polygon) is called a parallelogram if its opposite sides are parallel and are of equal length. The perimeter of a parallelogram is equal to the sum of lengths of all four sides.

In general, the perimeter of a parallelogram with adjacent sides a and b is given by the formula:

P = 2 × (a + b).