Question

IN a building there are 15 cylinder pillars. The radius of each pillar is 24 cm & height is 4 m. Find the total cost of painting the curved surface area of all pillars at the rate of Rs 10 per meter sq

Answer 1

Answer:

13.52

Step-by-step explanation:

C.S.A. of cylindrical =2πrh

⇒ C.S.A. of are pillar =2×

7

22

×28×4=704cm

2

⇒ C.S.A. of 24 pillars =24×704=16896cm

2

=16896×10

−4

m

2

=1.69m

2

⇒ Total cost Rs. 8×1.69=Rs.13.52

Answer 2

Answer:

Given :

• Number of pillars is 15.

• Radius of each pillar is 21 cm.

•Height of each pillar is 4 m.

•Rate of painting is 10 per m².

To find :

• cost of painting it's curved surface area?

Explanation:

1 m = 100 cm.

Therefore, 21 cm = 0.21 m.

Curved surface area of 1 cylinder =2π rh

→$2 \times \frac{22}{7 } \times 0.21 \times 4$

→2 x 22 x 0.03 × 4

→ 44 x 0.03 × 4

→1.32 x 4

→5.28

Therefore, the curved surface area of 1 pillar is 5.28 m².

C.S.A of 15 cylinder = 5.28 x 15

→79.2

Therefore ,the curved surface area of 15 pillars is 79.2 m².

Cost of painting 15 pillars = Rate x C.S.

→ 10 × 79.2

→792

Therefore the cost is =₹ 792.