Question

a hemispherical solid of radius 2 centimetre is to be painted find the cost of painting at the rate of rupees 70/ cm sq.​

Answer 1

Answer:

area of hemispherical solid = 3πr^2

= 3 * 3.14 * (2)^2

= 12 * 3.14

= 37.68 cm/sq

cost of painting = 37.68 * 70

= rupees 2,637.6

hope this helps you

Answer 2

Answer:

Let radii of the bases of two domes be r and R.

∴ 2πr = 17.6 ⇒ 2 x 22/7 x r = 17.6

⇒ r = 17.6 x 7/2 x 22 = 2.8 cm

and 2πR = 70.4 ⇒ 2 x 22/7 x R = 70.4

⇒ R = 70.4 x 7/2 x 22 = 11.2 cm

Now, area of two hemispherical domes = 2πr2 + 2πR2

= 2 x 22/7 x 2.8 x 2.8 x 2 x 22/7 x 11.2 x 11.2

= 49.28 + 788.48 cm2 = 837.76 cm2

Cost of painting at the rate of ₹10 per cm2 = 837.76 x 10

= ₹8377.6

Step-by-step explanation:

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