1. The expanded view of the side area of a cylinder is a square. The height of the cylinder is 28.26 cm, so its ground diameter is () cm? 2. Roll a rectangular paper of 16 cm long and 10 cm wide into a cylinder. When the height is 10 cm, the maximum perimeter of the bottom surface is () cm; when the height is 16 cm, the maximum perimeter of the bottom surface is () cm

1. The expanded view of the side area of a cylinder is a square. The height of the cylinder is 28.26 cm, so its ground diameter is () cm? 2. Roll a rectangular paper of 16 cm long and 10 cm wide into a cylinder. When the height is 10 cm, the maximum perimeter of the bottom surface is () cm; when the height is 16 cm, the maximum perimeter of the bottom surface is () cm

1、
Bottom circumference = height = 28.26 cm
So: bottom diameter = 28.26 △ 3.14 = 9cm
2、
When the height is 10 cm, the maximum perimeter of the bottom is (16) cm;
When the height is 16 cm, the maximum perimeter of the bottom is (10) cm
Note: for a cylinder made of rectangle, one side is high and the other side is the circumference of the bottom

The height of a cylinder is equal to 3 times of the radius of the bottom. The perimeter of the expanded side view of the cylinder is 37.12 cm, and the side area of the cylinder is ()

The radius is R:
（2πr+3r）*2=37.12
r=2
s=2πr*r=25.12

The circumference of the bottom surface is 18.84 meters, and the height is 5 meters

Let the radius be X
Bottom perimeter = 3.14 * x * 2 = 18.84
Then x = 3M
Then the side area = 18.84 * 5 = 94.2 square meters
2 bottom area = 3.14 * 3 * 3 * 2 = 56.52 M2
Total area = 56.52 + 94.2 = 150.72 square meters