Question

Find the cost of painting 15 cylindrical pillars of a
builiding at 2.50 per sq. m. If the diameter and
height of each pillar is 48 cm and 7 metres respec-
tively.
​

Answer 1

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Given:-

Diameter=48 m

$\sf \: So, \: radius= \frac{d}{2} = \frac{48}{2} = 24$

Height=7cm

$\sf \: Area=2\pi rh + 2\pi {r}^{2}$

$(2 \times \frac{22}{7} \times 24\times 7) +( 2 \times \frac{22}{7} \times24 \times 24)$

1056+3620.57=4674.69m²

Area of such 15 pillars=15×4674.69 = 70120.25cm²

Cost of painting 1m²=₹2.50

Cost painting 70120.35m² = 70120.35 × 2.50=₹143746.71

Hope it helps you.....