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Curved surface area of a cone is 308 cm2 and its slant height is 14 cm. Find the radius of the base and total surface area of the cone.
Curved surface area of cone =πrl= 308 cm2
Slant height =l = 14cm
=× r × 14 = 308 = r = 7 cm
Total surface area = πrl+πr2=308 +×72
= 462 cm2
A bus stop is barricaded from the remaining part of the road, by using 50 hollow cone made of recycled card-board. Each cone has a base diameter of 40 cm and height 1 m. If the outer side of each of the cones is to be painted and the cost of painting is Rs. 12 per m2. What will be the cost of painting all these cones. (Use π=3.14 and = 1.02).