The height of a right circular cone is 24 cm and the radius of its base is 7 cm. What is the cost of painting the curved surface area of the cone at the rate of ₹6 per cm2? (Take $π=\frac{22}{7}$)
Answer & explanation
Correct answer: option 2
We know that,
l = \(\sqrt {r^2 + h^2}\)
The curved surface area of the cone = πrl
The height of a right circular cone = 24 cm
The radius of base = 7 cm
Lateral height (l) = \(\sqrt {7^2 + 24^2}\)
l = 25 cm
The curved surface area of the cone = \(\frac{22}{7}\) × 7 × 25 = 550cm2
The cost of painting the curved surface area of the cone = 550 × 6 = Rs. 3300