1. Fill in the blanks (1) Write three irrational numbers:,,. (2) Write three groups of Pythagoras numbers:,,. (3) Write down three properties of diamonds:,,. (4) Write three ways to distinguish parallelograms:,,. (5) Write the proportional function of an image passing through the second quadrant and the fourth quadrant. (6) Write a linear function in which the value of y decreases with the increase of the value of x; (7) Write a binary linear equation with x = 2 and y = 3 as the solution. (8) The image passing through the point A (-2,6) has a proportional function as follows. (9) Among the 47 students in Class 1, Grade 8, Jiulongshan Middle School, there are 5 students with 12, 27 students with 13, 3 students with 14, and 3 students with 15. Therefore, the age pattern of this class is, and the median is. (10) Every inner angle of a regular polygon is 135, so the sum of the inner angles of this polygon is degrees. (1 1) After a 2 "line segment moves 3" to the right, the perimeter of the figure obtained by connecting the corresponding points is ". (12), the tractor fuel tank has 100 liter of oil, and it consumes 8 liters of oil every working 1 hour, so the functional relationship between the remaining oil quantity y (liter) in the fuel tank and the working time x (hour) is as follows. (13) Xiaoming bought nine stamps with a face value of 50 cents and 80 cents at Jiulongshan Post Office and spent them in 6.3 yuan. How many stamps did Xiaoming buy? If you buy X stamps with a face value of 50 cents and Y stamps with a face value of 80 cents, the equation can be listed as follows. Second, multiple-choice questions 1. The following figures that are not centrosymmetric are () A, parallelogram B, diamond C, rectangle D, isosceles trapezoid 2, and the perimeter of parallelogram is 50. Let its length be x and width be y, then the functional relationship between y and x is () a, y=25-x B, y=25+x C, Y = 25+X C, and the point on the image with function y=3x+2 is () a, (-1,1. (1) A quadrilateral with equal diagonals is a parallelogram; (2) A group of quadrilaterals with parallel and equal opposite sides are parallelograms; (3) The quadrilateral whose diagonals bisect each other is a parallelogram; (4) Two groups of quadrangles with equal opposite sides are parallelograms. a，4 B，3 C，2 D， 1 5。 In the following statement, the correct number is () (1). Only one of the triangles, quadrilaterals and regular hexagons can be divided vertically by the diagonal lines closely arranged. (3) the proportional function y=kx(k≠0). (5) A set of quadrangles with parallel opposite sides and another set of quadrangles with equal opposite sides are parallelograms A, 2 B, 3 C, 4 D and 5 3, respectively, and the solution is 1, and the regular triangle ABC with side length of 4. Establish an appropriate rectangular coordinate system and write the coordinates of each vertex. The bottom of the 2.5-meter-long ladder is 2 meters away from the wall. Can the top of this ladder reach the 4.5-meter wall? After learning the "rectangle" section, Xiao Ming wants to check whether the door at home is rectangular, but the only tools he can use are a graduated 20cm ruler and a roll of cotton thread. Can he check with these tools? Please help him design a test method. (Requirements: the scheme design is reasonable and the language description is clear and fluent). 4. The image of the proportional function y=k 1x and the image of the linear function y=k2x-9 all pass through the point P(3, -6). (1) Find the values of k 1 and k2. (2) Draw the images of these two functions in the same rectangular coordinate system. (3) If the linear function intersects the X axis at point A, find the coordinates of point A. 5.(6 points) A professional fish farmer in Shuanghe Village put 500 grass seedlings in the fish pond at the beginning of the year. Half a year later, 17 grass carp were randomly fished out, and the weight was as follows: grass carp mass (kg)1.501.601.70 65438+.

(1) Find the mode and average of these grass carp masses (the calculation result is kept in the second place after the decimal point). (2) What is the estimated total mass of 500 grass carp put in this fish pond at the beginning of this year?