Inner diameter 10.5cm
The cost of tin-plating it on the inside at the rate of Rs 16 per 100 cm2.
We know that
Formula for Surface area of hemispherical bowl = 2πr²
= 2×(22/7)×(5.25)2 = 173.25cm²
Cost of tin-plating 100 cm² area = Rs 16
So, Cost of tin-plating 1 cm² area = Rs 16 /100
Cost of tin-plating 173.25 cm² area = Rs. (16×173.25)/100 = Rs 27.72
Therefore, the cost of tin-plating the inner side of the hemispherical bowl at the rate of Rs 16 per 100 cm² is Rs 27.72.