Question

A cylindrical pipe has an outer diameter or 14 cm and inner diameter of 11.2 cm. Its length is 20 cm. It has to be painted on its outer and inner surfaces, as well as on its rims at the top and bottom. If the rate of painting is 0.07 per cm square, find the total cost of painting the pipe​

Answer 1

Answer:

• The Total cost of Painting is ₹118.64.

Step-by-step explanation:

Given,

• A cylindrical pipe has an outer diameter or 14 cm and inner diameter of 11.2 cm.
• Its length is 20 cm.
• . It has to be painted on its outer and inner surfaces, as well as on its rims at the top and bottom.
• If the rate of painting is 0.07 per cm square.

To Find,

• The total cost of painting the pipe.

Solution,

Outer diameter = 14 cm •••[Given]

So,

• The Radius of Outer Cylinder, R= 7 cm

Inner diameter = 11.2 cm •••[Given]

So,

• The Radius of Inner Cylinder, r = 5.6 cm

CSA of Outer Cylinder = 2πRh

• ➤ CSA = 2 × 22/7 × 7 cm × 20 cm
• ➤ CSA = 2 × 22 × 20 cm²
• ➤ CSA = 880 cm²

The CSA of Outer Cylinder is 880 cm².

CSA of Inner Cylinder = 2πrh

• ➤ CSA = 2 × 22/7 × 5.6 cm × 20 cm
• ➤ CSA = 2 × 22 × 0.8 × 20 cm²
• ➤ CSA = 704 cm²

The CSA of Inner Cylinder is 704 cm².

Area of Both Rims = 2(πR² - πr²)

• ➤ Ar(Both Rims) = 2π(R² - r²)
• ➤ Ar(Both Rims) = 2π[(7cm)² - (5.6cm)²]
• ➤ Ar(Both Rims) = 2π[49cm² - 31.36cm²]
• ➤ Ar(Both Rims) = 2π[17.64cm²]
• ➤ Ar(Both Rims) = 2 × 22/7 × 17.64cm²
• ➤ Ar(Both Rims) = 110.88 cm²

The Area of Both Rims is 110.88 cm².

The Area painted = CSA of Outer Cylinder + CSA of Inner Cylinder + Area of Both Rims

• ➤ The Area painted = 880 cm² + 704 cm² + 110.88 cm²
• ➤ The Area painted = 1694.88 cm²

The Area painted is 1694.88 cm².

The Cost of Painting = ₹0.07 per cm²

The Total cost of Painting = ₹0.07/cm² × 1694.88 cm²

• ➤ The Total cost of Painting = ₹118.64

The Total cost of Painting is ₹118.64.

Required Answer,

• The Total cost of Painting is ₹118.64.

Answer 2

Answer:

Step-by-step explanation:

ans is 118.64 by formula 2 pie r1 h + 2pier2h + 2pier1square-r2square