Fill in the blanks (3 points for each small question, 30 points for * * *)
1、 = 。
2. Decomposition factor: =.
3, known:, simplified =
4. Scientific counting method:-0.00214 =; 0.00002 14= .
5. When x=, the value of the score is equal to zero.
6. The circumference of a diamond is 52㎝, one diagonal is 24㎝, and the other diagonal is 24㎝. The area is ÷2.
7. The outer angles of a polygon are all equal, 720, and the sum of the inner angles of this polygon is.
8. If the perimeter of a parallelogram is 30 and the difference between two adjacent sides is 3, the lengths of the two adjacent sides are respectively.
9. If the length of one diagonal of a rectangle is 10㎝, then the perimeter of the quadrilateral surrounded by the midpoints of other sides is.
10, the base angle of an isosceles trapezoid is 600, the waist length is 10㎝, and the upper base length is 3㎝, so its circumference is and its area is.
Second, multiple-choice questions (3 points for each question, ***24 points)
Title 1 2 3 4 5 6 7 8
answer
1, the following proposition is incorrect ()
A quadrilateral whose diagonals bisect each other is a parallelogram.
A quadrilateral with equal diagonal lines is a trapezoid.
A quadrilateral with equal diagonal and bisector is a rectangle.
D. Quadrilaterals whose diagonals are perpendicular to each other and are split in two are diamonds.
2. The result of calculation is ()
A, B, C, D,
3. In the following questions, the correct calculation is ()
A, B,
C, D,
4, the value of the score is ()
A, 1 B,-1 c, 1 or-1 d, or
5, if, simplify ()
A, B, C, D and II
6. In a line segment, a straight line, an equilateral triangle, a parallelogram and a rectangle, it is both an axisymmetric figure and a centrally symmetric figure ().
a，2 B，3 C，4 D，5。
7. The quadrilateral obtained by sequentially connecting the midpoints of the sides of the quadrilateral with equal diagonal lines is ().
A, general quadrilateral b, rectangle c, isosceles trapezoid d, diamond
8, the following four propositions, the number of wrong propositions is ()
① The sum of the two waists of a trapezoid is greater than the difference between the two bottoms; ② A trapezoid with two equal angles is an isosceles trapezoid.
There may be three equal sides in a trapezoid. There must be an acute angle and two obtuse angles in a trapezoid.
a， 1 b，2 c，3 d，4
Third, answer questions; (65438 questions+4 points for 0, 2 and 3, 5 points for 4, 5 and 6 questions, 6 points for 7 and 8 questions and 7 points for 9 questions. ***46 points)
1, decomposition factor:
2、
3、
4. Simplify the assessment: In ...
5. Solve the equation:
6. From 20 small cards with 1~20 written on them, randomly select one card and try to find the probability of the following events.
A, the math on this card is a multiple of 5. The numbers on this card are prime numbers.
7. Cars are 24 kilometers faster than walking, and bicycles are faster than walking 12 kilometers. Someone starts from a place, walks 4 kilometers first, then arrives at b place by car 16 kilometers, and then returns to a place by bike. It takes the same time to go back and forth, so ask the person's walking speed.
8. As shown in the figure, at △ABC, ∠ACB=900, D and E are the midpoint of AB and AC respectively, and E is on the extension line of BC, ∠FEC=∠A, which proves that the quadrilateral DEFC is a parallelogram.
9. As shown in the figure, it is known that in □ABCD, EF‖BC, AB and CD intersect at E and F, DE and AF intersect at M, CE and BF intersect at N ... Verification: MN= AB.