Question

in a building there are 30 pillars.The diameter is 56 and hieght is 4m.Find the total cost of painting the curved surface area of all pillars at the rate of 80 RS PER METER SQUARE​

Answer 1

Correct question :

In a building there are 30 pillars. The diameter is 56 cm and height is 4m. Find the total cost of painting the curved surface area of all pillars at the rate of 80 RS PER METER SQUARE​

Given :

In a building there are 30 pillars. The diameter is 56cm and height is 4m.

To find :

Find the total cost of painting the curved surface area of all pillars at the rate of 80 RS PER METER SQUARE​ .

Solution :

Diameter of pillar = 56 cm

∴ Radius of pillar = 56/2 = 28 cm = 0.28 m

Height of pillar = 4 m

∴ CSA of 1 pillar = 2πrh

⇒ CSA of 1 pillar = 2 * 22/7 * 0.28 * 4

⇒ CSA of 1 pillar = 2 * 22 * 0.04 * 4

⇒ CSA of 1 pillar = 7.04 m²

There are 30 pillars.

∴ Total CSA = (30 * 7.04) m²

∴ Total CSA = 211.2 m²

Now, cost of painting = Rs.80/m²

∴ Total cost of painting = (80 * 211.2) Rs.

∴ Total cost of painting = Rs. 16896

∴ Total cost of painting all the pillars = Rs. 16896