A wooden toy is in the form of a cone surmounted on a hemisphere. The diameter of the base of the cone is 16 cm and its height is 15 cm. Find the cost of painting the toy at Rs. 7 per 100 cm2.


From the figure,


Radius of the hemisphere = 8 cm


Height of the cone = 15 cm


Lateral length of the cone = √(h2 + r2) = √(152 + 82) = 17 cm


Curved surface area of hemisphere = 2πr2


Curved surface area of the cone = πrl


Total curved surface area of the toy = 2πr2 + πrl


Total curved surface area of the toy = 2 × (22/7) × 82 + (22/7) × 8 × 17


Total curved surface area of the toy = 829.714 cm2


Cost of painting the toy at Rs. 7 per 100 cm2


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