First, think carefully and fill in carefully. (24%, 8 ~ 13, 2 points for each small question, and the rest 1 point. )

1, write the ratio of the divisor of 1, 18: (1: 3 = 2: 6).

2. If y= 15x, X and Y are in (positive) proportion; If y= 15 x, then x and y are inversely proportional.

3. In proportion, the two external terms are reciprocal, one is 37 and the other is (7/3).

4. The area of triangle is fixed, and the base and height are in (inverse) proportion; The height of the cone is constant, and its volume is proportional to the area of the bottom.

5. Draw the distance of 15km with a 3cm line segment on the map, then the scale of this map is (1:500000); On the map with the scale of 1∶2000, the line segment of 6 cm represents the actual distance (120) m, and the actual distance 180 m should be drawn (9) cm on the map.

6. The diameter of the bottom of the cylinder is 4 decimeters, the height is 0.5 decimeters, and its lateral area is (6.28) square decimeters; Its surface area is (3 1.4) square decimeter; Its volume is (6.28) cubic decimeter.

7. The radius of the bottom surface of the cylinder is 2cm, and when the side surface is unfolded, it is square, and the volume of the cylinder is (50.24) cubic centimeters.

8. When the side of the cylinder is unfolded, it is a square with a side length of 12.56 cm, and the diameter of the bottom of the cylinder is (4) cm.

9. The volume difference between a cone and a cylinder with the same base and height is 30 cubic centimeters. The volume of this cone is (15) cubic centimeters.

10. Cylinders and cones have the same bottom area and volume. The height of the cone is 3.6 decimeters, and the height of the cylinder is (10.8) decimeters.

1 1, a cylinder with a surface area of 50 square centimeters and a bottom area of 15 square centimeters. Put two such cylinders together to form a large cylinder with a surface area of (70) square centimeters.

12. The bottom radius of the conical part is 2cm, the height is 6cm, and the volume of this part is (25.438+02) cubic cm.

Second, choose carefully and sit in the right position. ( 15%)

1, if 3a=4b, then a: b = (②).

①3∶4 ②4∶3 ③3a∶4b

2. Flight speed and time of passenger planes flying from Beijing to Shanghai (②).

① Direct ratio ② Inverse ratio ③ Out of proportion.

3. Two related quantities (③).

① Direct ratio ② Inverse ratio ③. Not necessarily proportional.

On a map, the actual distance of 30 kilometers is represented by a line segment of 20 cm, so the scale of this map is (③).

① 1∶ 1500 ② 1∶ 15000 ③ 1∶ 150000 ④ 1∶ 1500000

5. The volume of a cylinder is constant and its height is inversely proportional to (③).

① Bottom radius ② Bottom area ③ Bottom circumference ④ Bottom diameter

6. Two proportions in the following group (③) cannot constitute a proportion.

① 7:8 and 14: 16 ②0.6:0.2 and 3:1③19:10 and 10:9.

7. The radius of the bottom surface of the cylinder is enlarged by 3 times, the height is unchanged and the volume is enlarged (②).

①3 times, ②9 times, ③6 times.

8. Knead a cylindrical plasticine ball into a cone with the same bottom as it, and pinch it high (②).

① Zoom in 3 times; (2) 3 times smaller; ③ Magnify 6 times; (4) reduced by 6 times.

9. On a map with a scale of 200 1, the length of a part is measured to be 2 cm, and the actual length of the part is ④.

① 4m ② 1m ③ 0. 1mm ④ 0.4mm。

Third, carefully scrutinize and be a good referee. ( 10%)

1, the number of copies subscribed to> is out of proportion to the amount of money. (√)

The area of a square is proportional to the length of its sides. (×)

3. The number of days is fixed, and the daily coal consumption is inversely proportional to the total coal consumption. (×)

It is easy to see the quantity from the histogram. ( √ )

5. The formula consisting of two ratios is called proportion. ( × )

6. If 8A = 9B, then b: a = 8: 9 (√).

7. The energy composition ratios of 15: 16 and 5: 6. ( × )

8. The volume ratio of cylinder to cone is 3∶ 1. ( √ )

9. When the height of a cylinder is doubled, its volume is doubled. ( √ )

10, the volume of a cone is 24 cubic centimeters, (Green Garden Primary and Secondary Education Network/Thread-174036-1.html) Its height is 4 centimeters, and its bottom area is 18 square centimeters. ( √ )

Fourth, carefully examine the questions and calculate them carefully.

1, write directly. (9%)

1- + = 6/5 1÷ × =4/9 0.5- +0.5- = 3/5

8. 1+ =8.35 ( + )×24= 14 7÷ ×7÷ =4

9-0.9=8. 1 72÷0.4= 180 1.25×8= 10

2. Solution ratio. ( 12%)

0.7x =145 8: 30 = 24: x35: 67 = x: 54 solution: 14x = 0.7x5 solution: 8x = 30×24 solution: 6/7x = 3/5× 5/4.

X = 3.5÷ 14 X = 720÷8 x = 3/4÷6/7

X = 0.25 x = 90 x = 7/8

4024 = 5×6.5:X = 3.25:4 23:56 = X:9 Solution: 40x = 24×5 Solution: 3.25x=6.5×4 Solution: 5/6x = 2/3× 9.

40x = 120 3.25x=26 5/6x=6

X = 3 x=8 x=36/5

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5. Go into life and solve problems. (30%)

1, a pesticide, is prepared from liquid medicine and water according to the ratio of 1: 100. How many kilograms of liquid medicine does it take to prepare 505 kilograms of this pesticide?

Each serving: 505÷( 100+ 1)=5 kg of liquid medicine: 5× 1=5 kg.

A: It needs 5 kilograms of potions.

5. A cylindrical reservoir with a bottom circumference of 365,438+0.4m and a depth of 2.4m measured from the inside, and its inner wall and bottom are coated with cement.

(1) What is the plastering area?

R: 3 1.4 ÷ 3. 14 ÷ 2 = 5m。

Bottom area: 5× 5× 3.14 = 78.5m2.

The plastering area is 31.4× 2.4+78.5 =153.86m2..

How many tons of water can this reservoir hold? (weight of water per cubic meter is 1 ton)

78.5×2.4× 1= 188.4 tons