a hemispherical bowl made of brass has inner diameter 10.5 find the co

1.	a hemispherical bowl made of brass has inner diameter 10.5 find the cost of tin plating it on the inside at the rate of 16rupees per 100 cm square
Answer» Given : DIAMETER of a hemispherical bowl made of BRASS = 10.5 cm Cost of tin plating 100 cm² = Rs. 16 To find : Cost of tin plating the hemispherical bowl Concept : → Formula to calculate RADIUS :- $\boxed{ \sf \pmb{Radius = \dfrac{Diameter}{2}}}$ → Formula to calculate Curved SURFACE area :- $\boxed{ \sf \pmb{Curved~~surface~~area= 2\pi r^2}}$ where, Take π = 22/7 r = radius Solution : Firstly, we will calculate the radius of the bowl :- Radius :- $\\ \dashrightarrow\sf \quad Radius = \dfrac{Diameter}{2}$ $\\ \dashrightarrow\sf \quad Radius = \dfrac{10.5}{2}$ $\\ \dashrightarrow\sf \quad Radius = \dfrac{ \not10.5}{ \not2}$ $\\ \dashrightarrow\sf \quad Radius = 5.25$ $\\ \sf \pmb{ \quad Radius \: of \: the \: bowl = 5.25 \: cm}$ Now, calculate the CSA of the bowl. $\\ \dashrightarrow \sf \quad CSA = 2\pi r^2$ $\\ \dashrightarrow \sf \quad CSA = 2 \times \dfrac{22}{7} \times 5.25 \times 5.25$ $\\ \dashrightarrow \sf \quad CSA = 2 \times \dfrac{22}{ \not7} \times \not5.25 \times 5.25$ $\\ \dashrightarrow \sf \quad Circumference = 2 \times 22 \times 0.75 \times 5.25$ $\\ \dashrightarrow \sf \quad Circumference = 173.25$ $\\ \sf \pmb{\quad CSA \: of \: the \: bowl = 173.25 \: cm^2}$ Cost of tin plating 100 cm² of the bowl = Rs. 16 Cost of tin plating 1 cm² of the bowl = 16 ÷ 100 = Rs. 0.16 Cost of tin plating the hemispherical bowl = Cost of tin plating 1 cm² of the bowl × CSA of the bowl $\\ \dashrightarrow \sf \quad Cost =0.16 \times 173.25$ $\\ \dashrightarrow \sf \quad Cost = 27.72$ $\\ \sf \pmb{ Cost \: of \: tin \: plating \: the \: bowl=Rs \: 27.72}$ ━━━━━━━━━━━━━━━━━━━━━━ Know More : Area of circle = πr² Circumference = 2πr Diameter = 2 × Radius Surface area of sphere = 4πr² Volume of cylinder = πr²h Volume of cone = 1/3 πr²h Curved surface area of cone = πrl Total surface area of cone = πrl + πr²h Total surface area of cylinder = 2πrh + 2πr²