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 cm^{2}.

From the figure,

Radius of the hemisphere = 8 cm

Height of the cone = 15 cm

Lateral length of the cone = √(h^{2} + r^{2}) = √(15^{2} + 8^{2}) = 17 cm

Curved surface area of hemisphere = 2πr^{2}

Curved surface area of the cone = πrl

Total curved surface area of the toy = 2πr^{2} + πrl

⇒ Total curved surface area of the toy = 2 × (22/7) × 8^{2} + (22/7) × 8 × 17

⇒ Total curved surface area of the toy = 829.714 cm^{2}

Cost of painting the toy at Rs. 7 per 100 cm^{2}

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