Find the cost of painting 15 cylindrical pillars of a building at Rs.

1.	Find the cost of painting 15 cylindrical pillars of a building at Rs. 2.50 per square metre if the diameter and height of each pillar are 48 cm and 7 metres respectively.
Answer» It is given in the question that, Diameter of the cylindrical pillars = 48 cm Hence, The radius of the cylindrical pillars = \(\frac{48}{2}\) = 24 cm = 0.24 m Height of the cylindrical pillars = 7 m Now, Lateral surface area of one pillar = \(\pi dh\) \(=\frac{22}{7}\times0.48\times7\) = 10.56 m² Now, The surface area to be painted = total surface area of 15 pillars = 15 × 10.56 = 158.4 m² Therefore, The total cost of painting = Rs(158.4 × 2.5) = Rs 396

Find the cost of painting 15 cylindrical pillars of a building at Rs. 2.50 per square metre if the diameter and height of each pillar are 48 cm and 7 metres respectively.

Answer»

It is given in the question that,

Diameter of the cylindrical pillars = 48 cm

Hence,

The radius of the cylindrical pillars = \(\frac{48}{2}\)

= 24 cm

= 0.24 m

Height of the cylindrical pillars = 7 m

Now,

Lateral surface area of one pillar = \(\pi dh\)

\(=\frac{22}{7}\times0.48\times7\)

= 10.56 m²

Now,

The surface area to be painted = total surface area of 15 pillars

= 15 × 10.56

= 158.4 m²

Therefore,

The total cost of painting = Rs(158.4 × 2.5)

= Rs 396