Question

A hemispherecall dome of bulding needs painted.if the area of the base is 24.64 m square , find the cost painting it given the cost of is rupees 5per 100cm square
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Answer 1

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Circumference of circle = 2πr

⇒ 17.6 = 2*22/7*r

⇒ 44r = 17.6*7

⇒ r = 123.2/44

⇒ Radius = 2.8 m or 280 cm

Now, Curved surface area of the hemisphere = 2πr²

⇒ = 2*22/7*280*280

⇒ = 3449600/7

⇒ = 492800 sq cm

Cost of painting = Rs. per 100 sq cm

Total cost of painting = (492800*5)/100

Total cost of painting = Rs. 24640

Answer 2

Circumference of circle = 2πr

⇒ 17.6 = 2*22/7*r

⇒ 44r = 17.6*7

⇒ r = 123.2/44

⇒ Radius = 2.8 m or 280 cm

Now, Curved surface area of the hemisphere = 2πr²

⇒ = 2*22/7*280*280

⇒ = 3449600/7

⇒ = 492800 sq cm

Cost of painting = Rs. per 100 sq cm

Total cost of painting = (492800*5)/100

Total cost of painting = Rs. 24640