Question

A closed cylindrical tank of diameter 7 cm and height 4 cm is made from sheet of metal.How much sheet of metal is required? *
561cm²
615cm²
156cm²
165cm²
Help!!!
I don’t need theory, i just need…
What is the correct option?

Answer 1

solution :-

Here , a closed cylinder is made from sheet of metal

Therefore,

Area of metal sheet = Total surface area of cylinder.

Here,

Diameter of cylinder = 7cm

Radius of cylinder = 7/2 cm

Height of cylinder = 4cm

As we know that,

TSA of cylinder = 2πr(r + h)

TSA of cylinder=2 * 22/7 * 7/2 (7/2 + 4)

TSA of cylinder = 22 ( 7/2 + 4 )

TSA of cylinder = 22 ( 7 + 8 / 2 )

TSA of cylinder = 22 ( 15/2 )

TSA of cylinder = 22 * 15/2

TSA of cylinder = 11 * 15

TSA of cylinder = 165cm^2

Hence, The area of metal sheet is 165cm^2 $.$

Option 4 is your answer mate

Answer 2

Given

• Diameter of cylinder = 7 cm
• Height of cylinder = 4 cm

To find

• How much metal sheet is required

Solution

Amount of metal sheet = Surface area of cylinder

• T.S.A = 2πr(r + h)

Where :-

• π = 22/7
• r = radius
• h = height

We have diameter (d) = 7 cm

Then, d = 2r

Hence, r = d/2

• r = 7/2
• r = 3.5

Substituting we get :-

• 2πr(r + h)
• 2 × 22/7 × 3.5 (3.5 + 4)
• 2 × 22/7 × 3.5 (7.5)
• 44/7 × 26.25
• 165

Hence, the total surface area of cylinder or the amount of sheet of metal for a close cylindrical tank is 165 cm²