the length of a roller is 40 cm and diameter is 21 cm It takes 300 complete Revolution to move once over to level the floor of a room find the area of room in metre square
Answers
Given, the length of a roller is 40 cm and its diameter is 21 cm. Now, radius of the roller r = 21/2 cm Now, lateral surface area = 2*π*r*h = 2*(22/7)*(21/2)*40 {height = length = 40 cm} = (22/7)*21*40 = 22*3*40 = 2640 cm2 Now, area of the room = lateral surface area *number of revolutions = 2640*300 = 792000 cm2 = 792000/(100*100) {since 1 cm2 = 1/(100*100) m2} = 7920/100 = 79.29 m2 = 79.2 m2