The height of a cylinder is 20 cm. If the height is reduced by 5 cm, the surface area is reduced by 100 square cm. What is the volume of the original cylinder

The height of a cylinder is 20 cm. If the height is reduced by 5 cm, the surface area is reduced by 100 square cm. What is the volume of the original cylinder

The base circumference of a cylinder
=100/5
=20 cm
Original cylinder volume
=3.14 * [20 / (3.14 * 2)] square * 20
=636.94 cm3

After a cylinder is cut off 6cm, the surface area of the cylinder is reduced by 75.36 square centimeter
The original height of the cylinder is 16cm

75.36 △ 6 = 12.56 (CM) bottom perimeter
12.56 ﹣ 3.14 ﹣ 2 = 2 (﹣ cm) bottom radius
2 × 2 × 3.14 × 2 = 25.12 (cm2) two bottom areas
The surface area can be calculated only when the height is high

After a 16 cm long cylinder is cut off for 6 cm, its surface area is reduced by 37.68 square cm. What is the original surface area of the cylinder?

Circumference of circle: 37.68 △ 6 = 6.28 (CM)
Radius of circle: 6.28 △ 3.14 △ 2 = 1 (CM)
The sum of the area of the top and bottom of the cylinder: 3.14 × 1 & # 178; × 2 = 6.28 (square centimeter)
Side area of cylinder: 6.28 × 16 = 100.48 (cm2)
Surface area of original cylinder: 100.48 + 6.28 = 106.76 (cm2)