Question

in a building there are 24 cylindrical pillars. the radius of each pillar is 28 cm and height is 4 m. find the total cost of painting the curved surface area of all the pillars at the rate of 8 per m​

Answer 1

Answer:

FORMULA = 2πr(h+r)

2*22/7*28(400+28)

2*22/7*28*428

527296/7

75328

per metre cost is 8₹

so 75328*8=602624

NUMBER OF PILLER IS 24

so 602624*24=14462976

ANSWER IS = 14462976₹

Answer 2

$radius \: of \: cylinderical \: pillar \: r = 28cm = 0.28 \\ height \: h = 4m \\ curved \: surface \: area \: of \: a \: cylinder = 2\pi rh \\ curved \: surface \: area \: of \: a \: pilliar = 2 \times \frac{22}{7} \times 0.28 \times 4 = 7.04m {}^{2} \\ cost \: of \: painting \: an \: area \: of \: 1m {}^{2} = rs.8 \\ therefore \: cost \: of \: painting \: 1689.6m {}^{2} = 168.96 \times 8 =rs. 1351.68$