Question

16. A building has 14 cylindrical pillars, each of diameter 1 m and height 4.5 m. The curved surface of all
the pillars have to be painted leaving 15 cm from top and bottom. Find the cost of painting the pillars
at the rate of 25 per
m2
​

Answer 1

Answer:

The radius of the pillars are 1/2 m

The height is 4.5 m

The number of pillars is 14

The CSA of one pillars =2πrh

2×22/7×1/2×45/10

99/7 m²

The CSA of all the pillars =14×99/7

=198m²

We will not paint the pillars 15 cm from the top and bottom

so the total are that will not be painted is =30 cm

30cm= 30/10⁴ =3/10³ m²

The are the should be painted is =198- 0.003 m²

=197.997 m²

The cost is = 25×197997/1000

= 4949.925 RS

The cost of painting is 4949.925 RS

Hope this helps you friend

Answer 2

Answer:

4620 Rupees .

Step-by-step explanation:

Diameter of 1 pillar = 1m

= 100cm

Radius of Pillar = diameter \2

100cm\2 = 50cm

Height Of pillar = 4•5m

450 cm

without painted part = 15cm + 15 cm

= 30 cm

Height Of pillar to be painted = 450cm - 30cm =420cm

CSA Of pillar = 2Πrh

= 2×22\7×50cm ×420cm

= 13200 square cm

Converting 13200Sq. cm in m Sq.

= 132000 \10000 Sq. m

= 13•2 m Sq

1. CSA Of 1 pillar = 13.2 Sq m

CSA Of 25 pillar = 13.2 × 25 m Sq

= 184.8 m sq

Cost of painting 1 m sq.= 25 rupees

cost of painting 184.8 m sq = 25rupees × 184•8

4620 rupees

I hope this is helpful for you .