Question

The dome of a building is in the form of a hemisphere. Its diameter is 126 cm. Find
the cost of painting it at the rate of 20 per cm2.​

Answer 1

CSA of hemisphere =2πr^2

$= 2 \times 63 \times 63 \times \frac{22}{7} \\ = 2 \times 9 \times 63 \times 22 \\ = 24948 \: {cm}^{2}$

cost of painting

$= 24948 \times 20 = 498960$

hope it helps you