Question

a hollow cylinder of height 25 m is cut along the length to make a rectangular sheet. if the perimeter of this sheet is 402 m, calculate the surface area of the cylinder​

Answer 1

Answer:

The length of rectangular sheet will be equal to the circumference of the circle. Lateral surface area of the cylinder will be equal to the area of the rectangular sheet.

Lateral surface area of a hollow cylinder = 4224 cm²

Width of rectangular sheet = 33 cm

Let length of the rectangular sheet = l

Lateral surface area of cylinder = Area of rectangular sheet

4224 cm² = b × l

4224 cm² = 33 cm × l

l = 4224 / 33 cm = 128 cm

Thus, the length of the rectangular sheet be 128 cm

Perimeter of the rectangular sheet = 2 × (l + b)

= 2 × (128 cm + 33 cm)

= 2 × 161 cm = 322 cm

Thus, the perimeter of the rectangular sheet is 322 cm.