a rectangular piece of paper is 22cm in length and 10cm in width it is rolled into a cylinder along its length find the surface area of this cylinder
Anonymous:
u asked surface area
bu which surface area?
curved surface area or total surface area?
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Since rectangular piece of paper of rolled along its length.
∴ 2πr = 22
r = 22 × 7 / 2 × 22 = 3.5 cm
Height of cyclinder (h) = 10 cm
∴ Volume of cyclinder = πr2h
= 22 / 7 × 3.5 × 3.5 × 10
= 385 cm3.
Answered by
2
After rolled into cylinder
height of cylinder = 10 cm
length of rectangle becomes circumference of cylinder
⇒ 2πr = 22
r = 22/2π [ taking π = 22/7]
r = 22*7/2*22 = 3.5 cm
curved surface area of cylinder = 2πrh = 22*10 = 220 cm² [ 2πr = 22 ]
Total surface area = 2πrh + 2πr² = 220 + 2*3.5*3.5*22/7 = 220+77 = 297 cm²
height of cylinder = 10 cm
length of rectangle becomes circumference of cylinder
⇒ 2πr = 22
r = 22/2π [ taking π = 22/7]
r = 22*7/2*22 = 3.5 cm
curved surface area of cylinder = 2πrh = 22*10 = 220 cm² [ 2πr = 22 ]
Total surface area = 2πrh + 2πr² = 220 + 2*3.5*3.5*22/7 = 220+77 = 297 cm²
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