Question

A hemispherical dome of a building needs to be painted
.If the circumference of the base of the dome is 17.6 m, find the cost
of painting it, given the cost of painting is 5 per 100 cm².​

Answer 1

Answer:

Hope it helps ☺️

Explanation:

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