Question

A cylindrical pillar is 50 cm in diameter and 305 cm in height. Find the cost of painting the curved surface of the pillar at the rate of rupees 12.50 per m square​

Answer 1

$\sf{\huge{\underline{\green{Given :-}}}}$

• A cylindrical pillar is 50 cm in diameter and 305 cm in height.

• The rate of painting is rupees 12.50 per m².

$\sf{\huge{\underline{\green{To\:Find :-}}}}$

• The cost of painting the curved surface of the pillar.

$\sf{\huge{\underline{\green{Answer :-}}}}$

According to the question,

We have , a cylindrical pillar

• Diameter = 50 cm = 0.50

• Radius = D/2 = 50/2 = 25 cm = 0.25 m

• Height = 305 cm = 3.5 m

We know that,

C. S. A of pillar = C. S. A of cylinder = 2πrh

➝ 2 × 22/7 × 0.25 × 3.5

➝ 2 × 22 × 0.25 × 0.5

➝ 44 × 0.125

➝ 5.5 m²

The rate of painting is rupees 12.50 per m².

1 m² = 12.50

➝ 5.5 m² = 5.5 × 12.50

➝ 68.75 m²

The cost of painting the curved surface of the pillar is Rs. 68.75 m² .