Question

The length of a roller is 40cm 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 meter square .

Answer 1

HEY BUDDY..!!!


HERE'S THE ANSWER..


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▶️ First we'll denote the given data

⏺️r ( radius ) = D / 2 = 21 / 2 cm = 21 / 200 m

⏺️l ( length ) = 40 cm = 0.4 m

♠️ Now area swapped in 1 revolution

✔️ length of roller ( l ) × circumference of roller

=> l × 2 π r

=> 0.4 × 2 × 22 / 7 × 21 / 200

=> 264 / 1000 m^2

♠️ Now for 300 revolutions we'll multiply it with 300

=> 264 / 1000 × 300

=> 26.4 × 3

=> [ 79.2 m^2 ]

♠️ Area swapped by that roller after 300 complete revolutions is 79.2 m2



HOPE HELPED..


JAI HIND..

:-)

Answer 2

hey asnitha...
here given that in 300 revolutions a roller complete a room..
so the area of room equal to curved surface area of roller (cylinder) × 300...
plz see the given image..
I hope u easily understand...
any queries plz comment...