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A rectangular sheet of paper 30cm×18cm can be transformed into the curved surface of a right circular cylinder in two ways i.e either by rolling the paper along its length or by rolling it along with its breadth. The ratio of the curved surface area of the two cylinders thus formed isa 1:1b 2:3c 3:4d 4:5 |
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Answer» Answer: CASE1: when the sheet is folded along its length : In this case, it forms a CYLINDER having height h1=18 CM and the CIRCUMFERENCE of its base equal to 30 cm. Let the radius of its base be r1. Then, 2pi r1=30 r1=15/pi. V1=pi r^2 h=pi*(15/pi)^2 cm3=4050/pi.cm3 Case.2 When the sheet folded along its breadth : Heights h2=30cm and the circumference of its base equal to 18cm. Let the radius be r2. Then, 2pi r2=18=(9/pi) V2=pi r^2 h=(pi*(9/11)^2) cm^3 =2430/pi cm^3. V1/v2=(4050/pi*pi/2430)=4050/2430=5/3 Ans.5:3. Step-by-step explanation: |
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