English

A Roller Has a Diameter of 1.4 M. Find : (I) Its Circumference ; (Ii) the Number of Revolutions It Makes While Travelling 61.6 M.

Advertisements
Advertisements

Question

A roller has a diameter of 1.4 m. Find :
(i) its circumference ;
(ii) the number of revolutions it makes while travelling 61.6 m.

Sum
Advertisements

Solution

Diameter = 1.4 m

r = `1.4/2 = 0.7` m

∴ Circumference of roller = `2pir`

= `2 xx 22/7 xx 0.7 = 4.4` m

Revolutions made in 4.4 m distance = 1

Revolutions made in 1 m distance = `1/4.4`

Revolutions made in 61.6 m distance

= `1/4.4 xx 61.6 = 616/44 = 14`

Hence (i) 4.4 m (ii) 14

shaalaa.com
  Is there an error in this question or solution?
Chapter 22: Area of a Trapezium and a Polygon - Exercise 20 (D) [Page 235]

APPEARS IN

Selina Concise Mathematics [English] Class 8 ICSE
Chapter 22 Area of a Trapezium and a Polygon
Exercise 20 (D) | Q 15 | Page 235

RELATED QUESTIONS

In the given figure, ABCD is a rectangle of dimensions 21 cm × 14 cm. A semicircle is drawn with BC as diameter. Find the area and the perimeter of the shaded region in the figure.


A 36-m-long, 15-m-board verandah is to be paved with stones, each measuring 6 dm by 5 dm. How many stones will be required?


In the given figure, ABCD is a quadrilateral in which diagonal BD = 24 cm, AL ⊥ BD  and CM ⊥ BD such that AL = 9 cm and CM = 12 cm. Calculate the area of the quadrilateral.  

 


In the following figure, there are three semicircles, A, B and C having diameter 3 cm each, and another semicircle E having a circle D with diameter 4.5 cm are shown. Calculate:

(i) the area of the shaded region

(ii)  the cost of painting the shaded region at the rate of 25 paise per cm2 , to the nearest rupee.

 


Write the area of the sector of a circle whose radius is r and length of the arc is l. 


In the given figure, ABCD is a rectangle inscribed in a circle having length 8 cm and breadth 6 cm. If π = 3.14, then the area of the shaded region is:


The wheel of a cart is making 5 revolutions per second. If the diameter of the wheel is 84 cm, find its speed in km per hour. [Take `π = 22/7`.]


The given figures show a rectangle ABCD inscribed in a circle as shown alongside.
If AB = 28 cm and BC = 21 cm, find the area of the shaded portion of the given figure.


A wire, when bent in the form of a square; encloses an area of 196 cm2. If the same wire is bent to form a circle; find the area of the circle.


Lalitha wants to buy a round carpet of radius is 63 cm for her hall. Find the area that will be covered by the carpet


Share
Notifications

Englishहिंदीमराठी


      Forgot password?
Use app×