Question

Hemispherical dome of stupa needs to be painted. The circumference of the base of dome is 17.6 m. How much will it cost to paint the dome, if it is given that the rate of painting is Rs 100 per square metre?​

Answer 1

Since only the rounded surface of the dome is to be painted we need to find the curved surface area of the hemisphere to know the extent of painting that needs to be done.

Now, circumference of base of the dome = 17.6 m Therefore 17.6 = 2πr

So, The radius of the dome =17.6×

2×22

7

m

= 2.8 m

The curved surface area of the dome =2πr

2

=2×

7

22

×2.8×2.8m

2

=49.28m

2

Now, cost of painting 100 cm

2

is Rs. 5

So, cost of painting 1 m

2

= Rs. 500

Therefore, cost of painting the whole dome

=Rs.500×49.28

=Rs.24640

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