Question

3. The length of a roller is 40 cm and its diameter is 21 cm. It takes 300 complete
revolutions to move once over to level the floor of a room. Find the area of the room in m2​

Answer 1

Step-by-step explanation:

$lateral \: surface \: area = 2\pi \: rh$

$area = 2 \times \frac{22}{7} \times \frac{21}{2} \times 40$

$area = 2640 {cm}^{2}$

$area \: of \: room = 2640 \times 300 = 792000 {cm}^{2} = 792 {m}^{2}$