Mr. Wang is going to use a cardboard to make a column. The following is the design drawing. Can you calculate the surface area of the column? The coloring part can't be added to the picture. Let me dictate it [a rectangle with a dotted line on the right and two circles and shadow parts in the dotted line. The width of the rectangle is 4 decimeters, right]

Four divided by two divided by two equals one decimeter
1 times 2 times 3.14 times 4 equals 25.12 square decimeters
The square of 3.14 times 1 equals 3.14 square decimeters
25.12 plus 3.14 times 2 equals 31.4 square decimeters

RELATED INFORMATIONS

1. Cut the square cardboard with side length of 20cm into four small squares of the same size. How many centimeters is the circumference of each small square
2. Cut a piece of square paper with a side length of 36 cm into four identical small rectangular pieces. The sum of the circumference of the four small rectangular pieces is larger than that of the original square How many centimeters has the circumference increased?
3. The right side of a right triangle is divided into 40 cm and 10 cm. Cut out a square and make it as large as possible. What is the square area Sorry, wrong number. Change the word "person" to "person", Can you solve it arithmetically?
4. The two right sides of a right triangle are 30cm and 40cm long, and the hypotenuse is 50cm long. The area of this triangle is______ Square centimeter
5. Cut the largest square from the sheet iron of a right triangle. What's the area of the square? (40 meters at the bottom) 40 / 10 = 4 40 * 10 / 2 / (1 + 4) = 40 (M2) 40 * 2 / 10 = 8 (m) 8 * 8 = 64 (m)
6. Cut a square on the sheet iron of a right triangle (bottom 40, height 10). The area of the square is as large as possible. How about the area of the square?
7. As shown in the figure, place the right angle vertex P of the triangle plate PMN on the diagonal BD of the square ABCD, and rotate the triangle plate around point P. the two right angle sides PM and PN of the triangle plate intersect AB at e and BC at f respectively (1) Verification: PE = PF (2) The quantitative relationship among be, BF and BP is expressed by equation and explained
8. As shown in Figure 1, slide the right angle vertex P of a right angle triangle plate on the diagonal BD of square ABCD, and make one right angle edge pass through point a all the time, and the other right angle edge intersects with BC at point E (1) Verification: PA = PE; (2) if the square in (1) is changed into a rectangle, and other conditions remain unchanged (as shown in Figure 2), and ad = 10, DC = 8, calculate AP: PE; (3) under the condition of (2), when p slides to the extension line of BD (as shown in Figure 3), please write the ratio of AP: PE directly
9. As shown in the figure, in the square ABCD, e is the midpoint of AB side, G and F are the points on AD and BC side respectively. If Ag = 1, BF = 2, ∠ GEF = 90 °, then the length of GF is______ ．
10. 1. It is known that the length of the hypotenuse of an isosceles right triangle is 10cm, and the waist length of the isosceles triangle is calculated 2. There are four identical right triangles to form a large square. As shown in the figure, it is known that the lengths of the two right sides of a right triangle are 6cm and 8cm respectively. To find the area of a large square, the Pythagorean theorem is used in both problems
11. A piece of cardboard 1.2 meters long and 70 cm wide is cut into a round teaching aid with a diameter of 30 cm. How many pieces can be cut at most?
12. Use a piece of square paper with a side length of 2 decimeters to form an empty cylinder. The circumference of the bottom surface of the cylinder is______ Decimeter, height is______ Decimeter, side area is______ Square decimeter
13. The area of a square is 16 square decimeters. How many square decimeters is the square area now?
14. Cut a piece of paper with an area of 8 square decimeters into the largest circle. What's the area of this circle?
15. If the side length of a square increases by 50 cm, the area will increase by 135 square meters. How many square meters is the original square area
16. A square, length and width increased by 50 decimeters, area increased by 135 square meters, square area The bull man, help
17. Use a piece of rectangular paper 15 cm long and 7 cm wide to cut out the largest square. What is the area of the largest square? How many square centimeters are left?
18. There is a rectangular paper 20 cm long and 15 cm wide. Cut the largest square. What is the area of the square
19. A piece of rectangular paper is 36 cm long and 20 cm wide. Fold the paper into the largest square. What is the square area?
20. Use a 15 cm long, 12 cm wide rectangular paper to cut the largest square. What is the area of the cut part?