Question

the length of a roller is 40cm and it's diameter is 21cm. it takes 300 complete revolution to move once over to level the floor of a room. find the area of the room in meter square

Answer 1

your answer is 4158000 cm ^2

Answer 2

hey friend here is your answer

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in a complete revolution the roller complete the distance of it's own circumference.

the radius of the roller is =21/2cm

so,the circumference of the roller=2×π×21/2 cm
=21π cm

the lengthof the roller is 40 cm

so,the curved surface area of the roller is=21π×40 cm square =84π cm square

so it is the area covered by the roller in a single revolution .

so the total area covered by the total revolution is=84π×300 cm square
=79168.134 cm square

so the area of the room is=7.9 metre square

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hope it helps you
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