Circumference of circle Application

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.

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)

Revolution If a bicycle has covered some distance with certain number of revolutions, we have following formulas Formula to find Distance travelled = Circumference x Number of revolutions

So, to convert cm to m, we divide the 3960 by 100 Example 2: The diameter of a bicycle wheel is 63 cm. How much distance will it cover in 20 revolutions? Solution Given : d= 63 , no. of revolution = 20 Distance travelled = Number of revolutions X Circumference Step1: Finding Circumference Distance covered in one rotation = Circumference of wheel Circumference of the wheel = πd =22 x 9 = 198 cm Therefore, Distance covered in one rotation = 198cm Step 2: Finding Distance for 20 revolution We know that, Distance travelled = Number of revolutions X Circumference Distance travelled in 20 revolutions = 20 X 198 cm = 3960 cm = 39m 60cm (Ans) 9 Divide 63 and 7 by 9 We know that 1m = 100cm, So, to convert cm to m, we divide the 3960 by 100 3960cm = 39m 60cm

Step1: Finding Circumference Example 3: A scooter wheel makes 50 revolutions to cover a distance of 8800 cm. Find the radius of the wheel. Solutions: Given : revolution=50 , distance=8800cm To Find: radius of wheel Step1: Finding Circumference We know that, Distance travelled = Number of revolutions X Circumference 8800 = 50 x Circumference Circumference = 176 cm Step2: Finding radius We know that, Circumference = 2πr 4 16 Divide 176 and 44 by 11 4 Divide 16 and 4 by 4 r= 4 x 7 = 28 cm (Ans)

Solution: Given: radius=70cm distance = 132m To Find : revolution Example 4 : The radius of a cart wheel is 70 cm. How many revolution does it make in travelling a distance of 132 m. Solution: Given: radius=70cm distance = 132m To Find : revolution Step1: Finding Circumference We know that, Circumference = 2πr 10 Divide 70 and 7 by 7 Circumference = 2 x 22 x 10 = 440cm Step 2: Finding number of revolution Distance travelled = Number of revolutions X Circumference 13200 = Number of revolutions X 440 We know that 1m = 100cm, So, to convert m to cm, we multiply 132m as cm 132m = 132 x 100 = 13200cm 1200 30 Divide 13200 and 440 by 11 40 Divide 1200 and 40 by 40 Number of revolutions = 30 (Ans)

Try these 1. A scooter wheel makes 50 revolutions to cover a distance of 2200 cm. Find the radius of the wheel. 2. The radius of a bus wheel is 28 cm. How many revolution does it make in travelling a distance of 88 m.