Perimeter

Perimeter:

Introduction to What is perimeter?

The perimeter is the total distance around the outside of a two - dimensional shape (2D). We can calculate it by adding together all the length of a shape. The perimeter of a polygon is the sum of the lengths of all its sides.

We can also define perimeter as : The distance around a figure is called the perimeter of the figure.

Closed Curve: A curve which begins and ends at the same point is called a Closed Curve.

Simple closed Curve : A closed Curve which doesn't intersect itself is called a Simple closed Curve.

Unit of Perimeter : Perimeter is 1-dimensional and is measured in linear units. Example such as feet or meters.


How to Calculate Perimeter of Different Shapes:

Q 1 : what is perimeter of a rectangle whose Length = 3cm and Breadth = 2 cm?

Let us find this in three different ways:

Sol 1: Perimeter of rectangle is 2cm+3cm+2cm+3cm = 10 cm

Sol 2: Perimeter of rectangle is (2 x 2cm ) + ( 2 x 3cm) = 4cm + 6 cm = 10 cm

Sol 3:Perimeter of a Rectangle = 2 x ( length + breadth ) = 2 x (3+2) = 2x5 =10cm

Q 2: Find the perimeter of a triangle with sides measuring 5 cm, 9 cm and 11 cm

Sol : Perimeter = 5 cm + 9 cm + 11 cm = 25 cm (we have simply added the sides).

Let us understand what parimeters are by looking at examples of Perimeters.

Examples for What is Perimeter

Q 1 : A rectangle has a perimeter of 36 cm. If its length is 9cm, what is its breadth?

Sol : Perimeter of rectangle = 36 cm
length of rectangle = 9cm

now twice the length = 2x9

=18cm
again twice the breadth = 36-18

= 18cm
Breadth = 18/2

= 9cm


Thus, The breadth of the rectangle = 9cm.

Q 2 : A square has a perimeter of 36cm. What is the length of each side?


Sol : Perimeter of the square = 36cm
Side of the square = perimeter/4
= 36/4

= 9cm
thus, side of square is 9cm

Q 3 : A triangle has a perimeter of 50 cm. If its two sides are of length 15cm and 19cm,
what is the length of third side?


Sol : Perimeter of a triangle = 50cm
length of two sides are 15cm and 19cm.
Length of the third side = 50-(15+19)cm.
= 50-34cm
= 16cm.
Thus the lengthof third side = 16cm.


Hope you like the above example of Perimeters.Please leave your comments, if you have any doubts.