1. The bottom area of a cone is 10cm in diameter and 15cm in height. How many square centimeters has the surface area increased when it is cut in two vertically along the bottom diameter? 2. A conical vessel is welded with a fan-shaped sheet iron with an arc length of 62.8cm [the joint is ignored]. What is the bottom area of the cone in square centimeter?

1. The bottom area of a cone is 10cm in diameter and 15cm in height. How many square centimeters has the surface area increased when it is cut in two vertically along the bottom diameter? 2. A conical vessel is welded with a fan-shaped sheet iron with an arc length of 62.8cm [the joint is ignored]. What is the bottom area of the cone in square centimeter?

10 * 15 = 150 square centimeter
3.14 * (62.8 divided by 3.14) square = 1256 square centimeters