1. Circumference of circle Application

2. Circumference of circle Application - Introduction
We know that perimeter is measuring the outside of any shape.
Let us learn how to calculate perimeter by small Illustration of using rope length.
Let us take a rope of x length and try reshaping the rope into a square as given below.
X length
From this, its clearly seen that Perimeter of a square = length of the rope.

3. Circumference of circle Application - Introduction
Now let us see 2nd illustration for Circle:
Let us take the same rope of x length and try reshaping it as a circle.
X length
What can you conclude from the illustration?
From the above illustration, we conclude that Circumference of a circle = length of the rope.
Therefore, if the rope of any particular length is reshaped into any shape , can become perimeter of that shape
(as far as circle, its circumference)

4. Incase of non circular ground Incase of circular ground
Fencing
Fencing is building a fence(or wall) around the ground.
If the ground is rectangle in shape , length of fence will be perimeter of rectangle
If the ground in circle in shape , length of fence will be circumference of circle
Incase of non circular ground
Incase of circular ground
Cost of fencing = perimeter x rate
Cost of fencing = circumference x rate

5. Step1: Finding Circumference We know that, Circumference = 2πr
Example 5: The radius of a circular flower garden is 56 m. What is the cost of fencing it at Rs.10 a metre ?
Solution Given: radius = 56m rate=Rs 10 per metre To Find: Cost of fencing
Step1: Finding Circumference
We know that, Circumference = 2πr 8
Divide 56 and 7 by 7
Circumference = 2 x 22 x 8 = 352 m
Step2: Finding Cost of fencing
Cost of fencing = circumference x rate
= 352 x 10 = 3520
Cost of fencing = Rs (Ans)

6. Step1: Finding Cirumference
Example 6 :
The cost of fencing a circular park at the rate of Rs.5 per metre is RS What is the radius of the park.?
Solution Given: rate = Rs 5 per metre, Cost of fencing = Rs To Find: radius
Step1: Finding Cirumference
Step2: Finding radius
We know that, Circumference = 2πr 5 20
Divide 220 and 44 by 11 4
Divide 20 and 4 by 4
r = 5 x 7 = 35 m (Ans)

7. Try these
1. The cost of fencing a circular park at the rate of Rs.10 per metre is RS What is the radius of the park? 2 . The cost of fencing a circular room at the rate of Rs. 20 per metre is Rs What is the radius of the park.