The radius of solid right circular cylinder is 21 cm and its height is 40 cm. What is the cost of painting the curved surface area of the cylinder at the rate of ₹20 per cm2?(Take $π =\frac{22}{7}$)
Answer & explanation
Correct answer: option 2
We know that,
Curved surface area of right circular cylinder = 2πrh.
We have,
Radius of the cylinder = 21 cm.
Height of the cylinder = 40 cm.
So, the curved surface area of circular cylinder = 2 × \(\frac{22}{7}\) × 21 × 40 = 5280 cm2
The cost of painting the curved surface area = 5280 × 20 = ₹105600