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 pillars at the rate of ₹8 per metre square

Answer 1

Radius of cylinderical pillars
= r = 28cm =0.28m
height ,h=4m
curved surface area of a cylinder =2πrh
curved surface area of a pillar= 2×22\6×0.28×4=7.04metresq.
Curved surface area of 24 such pillars = 7.04×24=168.96metresq.
cost of cementing an area of 1metresq. =Rs8
so,cost of painting 1689.6metresq.=168.96×8=Rs1,351.68

Answer 2

Answer:

Rs. 1351.68

Step-by-step explanation:

$\text{Radius of each pillar = 28 cm = 0.28 m}\\\\\text{Height of each pillar = 4 m}\\\\\text{CSA of 1 pillar = 2} \pi r h\\\\= 2 \times \dfrac{22}{7} \times 0.28 \times 4\\\\\\= \dfrac{49.28}{7}\\\\\\= 7.04 \: m^2\\\\\text{Area of 24 pillars = 7.04(24) = 168.96 cm}^2\\\\\text{Cost of painting per m ^2 = Rs. 8}\\\\\text{Total cost = Rs. 8} \times 168.96 = \textbf{Rs. 1351.68}$

Hope it helps!