1, fill in the blanks.

(1) The circumference of the cylinder bottom125.6cm, the height12cm, and its lateral area is ().

Square centimeters.

(2) The side area of a cylinder with a bottom radius of 3 cm and a height of 5 cm is () flat.

Square centimeter, the surface area is () square centimeter.

(3) wrapping a piece of white paper with a length of 8 decimeters and a width of 5 decimeters into a cylindrical paper tube, wherein the lateral surface of the paper tube

The area is () square decimeter.

(4) A cylinder with a bottom radius of 3 cm and a height of 15 cm has a flat surface area.

Square centimeters.

2. Judges.

(1) Surface area of cylinder = bottom area ×2+ bottom area × height. ( )

(2) The surface area of a cylinder must be larger than its side area. ( )

(3) The larger the bottom area of a cylinder, the larger its surface area. ( )

Step 3 choose.

(1) To make a cylindrical bucket without a cover, the required iron sheet area is ().

A. horizontal area+one base area B. horizontal area+two base areas.

C. (lateral area+bottom area) ×2

(2) The diameter of the bottom surface of the cylinder is10cm and the height is 4 decimeters. Its side area.

It's () square centimeters.

a . 1256 b . 3 14 c . 3 140d