After cutting off a 3 cm high section of a cylinder, the surface area is reduced by 18.84 square centimeters. How much is the volume of the cut off part of the cylinder

After cutting off a 3 cm high section of a cylinder, the surface area is reduced by 18.84 square centimeters. How much is the volume of the cut off part of the cylinder

2 * pi * r * 3 = 18.84, then r = 1. The final volume is pi × R × R × 3 = 9.42

There is a cylinder with a height of 10 cm. If its height is reduced by 2 cm, its surface area will be reduced by 18.84 square cm. What is the volume of the original cylinder?

What is the circumference of the base of the cylinder
18.84 △ 2 = 9.42 cm
What is the base radius of the cylinder
9.42 ﹣ 3.14 ﹣ 2 = 1.5cm
The original volume of the cylinder is
1.5 × 1.5 × 3.14 × 10 = 70.65 cm3