The length of a roller is 40cm and its diameter is 21cm it takes 300 complete revolutions to move once over to the floor of a room find the area of the room in m^2
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 cm^2
=> (21/2)*40 {height = length = 40 cm}
=>Now, area of the room = lateral surface area *number of revolutions
= 2640*300
= 792000 cm2
= 792000(100*100) {since cm2 = 1/(100*100) m2 }
= 7920/100
= 79.29 m^2
hope this will help......☺️
Answer:
79.29m²
Step-by-step explanation:
Lateral surface area of roller=2πrh
=2×(22/7)×(21/2)×40
=66×40
=2640cm²
Now, area of the room = lateral surface area ×number of revolutions
=2640×300
=792000 cm²
Change cm² into m²=7920000cm²
cm²=79.29m²
Hope it's help you