1. The side expansion of a cylinder is a square with a side length of 3.14 decimeters. What is the radius of the bottom of the cylinder

1. The side expansion of a cylinder is a square with a side length of 3.14 decimeters. What is the radius of the bottom of the cylinder

R = 0.5 decimeter
It can be seen from the expanded drawing that the circumference of the circle on the two bottom surfaces of the cylinder is the side length of the square, that is, 2 π r = 3.14 r = 0.5
It can be seen that the two circular ends of the cylinder are circles with a radius of 0.5 decimeters, and the height of the cylinder is exactly 3.14 decimeters

The height of a cylinder is 4 decimeters, and its side is square after expansion. Find the surface area of the cylinder
The following questions help to do out, give 300 points! 300! And the above question also need to be solved
(1) The bottom radius is 2 decimeters and the height is 7.3
(2) The perimeter of the bottom is 18.84 and the height is 5 meters
(3) A cone-shaped wheat pile has a circumference of 12.56 at the bottom and a height of 1.2. If each cubic meter of wheat weighs 750 kg, how many kg does it weigh
(4) If you subtract 2 cm from the height of a cylinder, the side area will be reduced by 50.24 square cm. How many cubic cm will its volume be reduced
(5) A cylinder with a height of 6 decimeters is cut vertically along the diameter of the bottom surface and divided into two parts on average. The surface area is increased by 48 square centimeters. What is the original volume of the cylinder

Let the radius of the circle on the bottom be r, then 2 ×Π× r = 4, and the solution is r = 2 / Π. So the volume of the cylinder = Π× (2 / Π) ＾ = 4 / Π cubic decimeter (1) the surface area = Π × 2 × 2 + 2 ×Π × 2 × 7.3 = 33.2 (2) what is the question? (3) the radius of the bottom = 12.56 △ 2 ×Π) = 2