The internal and external diameter of a hollow hemispherical vessel are 24cm and 25 cm respectively. The cost of paint 1sq .cm of surface is Rs7 . find the total cost to paint the vessel all over ignore the area of edges .
Answers
given,
internal diameter=21cm
internal radius=21/2=10.5cm
external diameter=25.2cm
external radius=25.2/2 =12.6cm
surface area of internal bowl=2πr²
=2(22/7)(10.5²)
=2×22×10.5×10.5/7
=693cm²
surface area of external bowl=2πR²
=2(22/7)(12.6²)
=2×22×12.6×12.6/7
=997.9cm²
surface area of ring=π(R²-r²)
=22/7(12.6²-10.5²)
=22/7(48.51)
=22×48.51/7
=152.46cm²
cost of internal bowl=693×0.1=69.3
cost of external bowl=997.9×0.1=99.79
cost of ring=152.46×0.1=15.246
cost of bowl=69.3+99.7+15.2=184.2
internal diameter=21cm
internal radius=21/2=10.5cm
external diameter=25.2cm
external radius=25.2/2 =12.6cm
surface area of internal bowl=2πr²
=2(22/7)(10.5²)
=2×22×10.5×10.5/7
=693cm²
surface area of external bowl=2πR²
=2(22/7)(12.6²)
=2×22×12.6×12.6/7
=997.9cm²
surface area of ring=π(R²-r²)
=22/7(12.6²-10.5²)
=22/7(48.51)
=22×48.51/7
=152.46cm²
cost of internal bowl=693×0.1=69.3
cost of external bowl=997.9×0.1=99.79
cost of ring=152.46×0.1=15.246
cost of bowl=69.3+99.7+15.2=184.2