Class name seat number

First, multiple-choice questions (3 points for each small question)

1. A virus is very small, with a radius of about 0.000000 16m, which can be expressed as () by scientific notation.

A.1.6×106m B.1.6×10-6m C.1.6×10-7m D.1.

2, in the line segment, diamond, regular quadrilateral, regular pentagon, ring these five kinds of graphics, both central symmetry and axial symmetry graphics is ().

1 (B)2 (C)3 (D)4

3. As shown in the right figure, in trapezoidal ABCD, AD‖BC, diagonal AC and BD intersect at point O, then triangles with equal areas in the figure have ().

A. 1 pair B.2, pair C.3 and pair d.4.

4. To manufacture a product, the original cost of each product was 200 yuan. Because the cost was reduced twice in a row, the cost is now 162 yuan, so the average cost is reduced every time ().

a、8.5% B、9% C、9.5% D、 10%

5. If 1 cube is represented by □, two cubes are superimposed and three cubes are represented by ■.

2008-2009 school year first semester third grade mathematics first monthly examination paper.

As shown in figure 1, the top view of the cylinder is

Figure 1 A B C D

2. The root of the unary quadratic equation is

A.B. C. D。

3. The following operation is correct ()

a . a2+a3 = a5 b . a2 a3 = a6 c .(-a2)3 = a6 d .(-a3)2 = a6

4. Factorization polynomial 25- 16x2, correct.

A.(5+4 times) (5-4 times) b .(5+ 16 times) (5- 16 times)

C.(25+ 16x)(25- 16x)d .(25+4x)(25-4x)

5. Which of the following Greek letters is an axisymmetric figure?