1 The area of the circle is equal to the area of the rectangle, and the radius of the circle is equal to the width of the rectangle. Find the length of the rectangle is 12CM and the radius of the circle is []CM. Let the width of a rectangle be x*x*π= 12*x, then the width is x= 12/π 2. A straight cylinder 2 meters long. The surface area of the remaining cylindrical wood decreased by 12.56 square decimeter. The original bottom area of cylindrical wood is [] square decimeter and the volume is [] cubic decimeter. The reduced surface area is actually the side of the cylinder. So you can get a circumference of 62.8, so the radius is 10 decimeter, and you can get the bottom area and volume. 3. Decompose 7 14 into prime factor 7 14=2*3*7* 17. 2. Application problem 1. Go to school to buy tables and chairs. If you buy a 15 table, you can buy 20 chairs. If you buy two chairs for a table, how many sets can you buy? Suppose each chair is 3 yuan, 20*3a/ 15=4a, then each table is 4 yuan, then each set is 4a+2*3a=6a, and the total * * * money is 15*4a=60a, then you can buy 6 sets of 2. A, B and C do the project, and A does it alone 15 days. 1* (115+1/20) remaining item c (1-6 *115) (65438) 3. A set of numbers * * * are six digits respectively; 2, 3, [], [], 9, 15 brackets indicate that I don't know. If the median is 7, what is the average? 6 and 8, 4. To produce a batch of parts, Party A makes 18 pieces per hour, and only Party B needs 12 hours to complete it. Now, Party A and Party B jointly manufacture these parts. The task is that the proportion of parts produced by Party A is 3: 5. Ask Party A how many parts are produced, and the working hours are the same, so the ratio of the number of parts produced is the ratio of speed. Party B produces 30 parts per hour, so the total number of * * * is 12 * 30 = 360, and that produced by Party A is 360*3/8.