Question

The total surface are of a right cicular is 687.72 sgc, it its radius
is 2.1 cm, find the height the cylinder,​

Answer 1

Given:

✰ The total surface area of cylinder (T.S.A) = 687.72 cm²

✰ The radius of cylinder = 2.1 cm

To find:

✠ The height of the cylinder.

Solution:

Here we will use formula of total surface area. As we are already provided with the total surface area and the radius of the cylinder. Putting the values in the formula and doing the required calculations, we will find out the height of the cylinder.

Let's find out...!

✭ Total surface area of cylinder (T.S.A) = 2πr (h + r) ✭

Where,

• r is the radius of the cylinder and h is the height of the cylinder.

Putting the values,

➛ 687.72 = 2 × 22/7 × 2.1 (h + 2.1)

➛ 687.72 = 44/7 × 2.1 (h + 2.1)

➛ 687.72 = 44/7 × 2.1h + 4.41

➛ 2.1h + 4.41 = 687.72 × 7/44

➛ 2.1h + 4.41 = 109.41

➛ 2.1h = 109.41 - 4.41

➛ 2.1h = 105

➛ h = 105/2.1

➛ h = (105 × 10)/2.1

➛ h = 1050/21

➛ h = 50 cm

∴ The height of the cylinder = 50 cm

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Answer 2

Given :

• The Total Surface Area of a right circular Cylinder is 687.72cm²
• Radius of Cylinder = 2.1cm

To Find :

• Height of Cylinder

Solution :

✰ As we know that, Total Surface Area of a Cylinder is given by 2πr × ( h + r ) where h and r stands for Height and Radius respectively.

⠀⠀

Putting the Values :

➟ T.S.A of Cylinder = 2πr × ( h + r )

➟ 687.72 = 2 × 22/7 × 2.1 × ( h + 2.1 )

➟ 687.72 = 44/7 × 2.1 × ( h + 2.1 )

➟ 687.72 = 44 × 2.1/7 × ( h + 2.1 )

➟ 687.72 = 92.4/7 × ( h + 2.1 )

➟ 687.72 = 13.2 × ( h + 2.1 )

➟ 687.72 / 13.2 = h + 2.1

➟ 52.1 = height + 2.1

➟ 52.1 - 2.1 = height

➟ 50cm = height

Thus Height of Cylinder is 50cm

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