Question

In a building there are 24 cylindrical pillars. The radius of each pillar is 28cm and height is 4cm. Find the total cost of painting the curved surface area of all pillars at the rate of rupee 8 per
${m}^{2}$
​

Answer 1

Answer:

,

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

$\huge \fcolorbox{red}{blue}{ \bf \green{₹13.52}}$

Step-by-step explanation:

QUESTION :-

In a building there are 24 cylindrical pillars. The radius of each pillar is 28 cm and height is 4 cm. Find the total cost of painting the curved surface area of all pillars at the rate of ₹8 per m².

___________________________

SOLUTION :-

A.T.Q.,

all 24 cylindrical pillars'

• radius (r) = 28 cm
• height (h) = 4 cm

So,

Firstly, we will find the Curved Surface Area (CSA) of the cylindrical pillar.

CSA of cylinder = 2πrh

[let π = 22/7]

CSA of given cylinder,

$\bf = > 2 \times \frac{22}{ \cancel7} \times \cancel {28}^{ \: 4} cm \times 4cm \\ \\ \bf = > 2 \times 22 \times 2 \times 4 {cm}^{2} \\ \\ \bf = > 704 {cm}^{2}$

____________________________

Now,

CSA of 1 pillar = 704 cm²

=> CSA of 24 pillars = 24 × 704 cm²

= 16896 cm²

____________________________

Then,

Change area into m² (from cm²)

We know that,

1 m² = 10000 cm²

=> 1 cm² = 1/10000 m²

=> 16896 cm² = 16896 ÷ 10000 m²

= 1.6896 m²

_________________________

Given that,

cost of painting 1m² = ₹8

so,

cost of painting 1.6896 m² = ₹8 × 1.6896

= ₹13.5168

≈ ₹13.52

Hence,

Total cost of painting is approximately ₹ 13.52.

___________________________

Hope it helps.

#BeBrainly :-)