2.5A=4B(A and B are not equal to 0). A: B = (): ().
3. The ratio of: to the simplest integer is ().
4. If =, then A and B are proportional ().
5. The volume of a cylinder with a base diameter and a height of 6 decimeters is ().
6. The radius of the cylinder bottom is 5m, the volume is157m3, and the height is () m..
7. In a proportion, two internal terms are reciprocal, one external term is and the other external term is ().
8. A rectangular land with a length of 75 meters and a width of 30 meters was drawn on the drawing, and the scale was () long and () wide.
9. The radius of the bottom of the cylinder is 2 cm and the height is 2 cm. Its side development is ()-shaped. The circumference of this figure is () cm and the area is () cm 2.
The ratio of 10 to: 8 is (). If you use it to write a ratio, this ratio can be ().
1 1. It is known that the relationship between A, B and C is A ÷ B = C, and if A is certain, B is directly proportional to C (). If c is certain, a and b are proportional ().
12, the number of students who passed the sixth-grade math contest accounted for the number of students who failed, and the passing rate of sixth-grade students in this competition was ().
13, the sum of the minuend, subtraction and difference is 40, the ratio of subtraction and difference is 3:2, the minuend is (), and the subtraction is ().
14, a kind of brine, is made by mixing salt and water at the ratio of 1: 100. Now, to prepare 8008 grams of this brine, 1 kg salt is needed.
15, the two external terms of a ratio are 5 and 6 respectively, and their ratio is 3, which is ().
16. On the map of China with the scale of 1: 400000, the distance between the two places is 30 cm, and the actual distance is () km.
17, () The statistical chart can not only show the quantity, but also clearly show the change of the quantity.
18, a certain length of iron wire is divided into several sections on average, and the length of each section is proportional to the number of sections.
Second, choose.
1, the following ratio, can be proportional to the ().
①3:4 ②4:3 ③ : ④ :3
2. Put 1 g salt into 100 g water, and the ratio of salt to brine is ().
① 100: 10 1 ② 1: 10 1 ③ 1:99 ④ 1: 100
3. In proportion, the product of two external terms is certain, and the two internal terms become ().
① Positive proportion ② Inverse proportion ③ Out of proportion ④ It is impossible to judge.
4. The existing three numbers 9, 3 and () can form a proportion.
① ② ④4 ④2
5. Solution ratio =2: 1, χ = ().
①6 ② 1.5 ③0.7 ④9
6, two reciprocal, they must be ().
① Positive proportion ② Inverse proportion ③ Out of proportion ④ It is impossible to judge.
7. Xiao Wang's height and weight are ().
① Positive proportion ② Inverse proportion ③ Out of proportion ④ It is impossible to judge.
8. The radius of the small circle is 2 cm, the radius of the big circle is 3 cm, and the ratio of the area of the small circle to the big circle is ().
①2:3 ②3:2 ③4:9 ④9:4
9, a project, the ratio of completed to this project is 3:5, the rest () for this project.
①60% ②40% ③20% ④ 166.6%
10, the distance on the drawing is 3cm, the actual distance is 1.5mm, and the scale is ().
① 1:20 ② 1:2 ③ 1:200 ④20: 1
1 1, the class size is certain, and the number of attendees and absentees is ().
① Positive proportion ② Inverse proportion ③ Out of proportion ④ It is impossible to judge.
12, a cylinder, if the height remains the same, the bottom area will be expanded by 3 times, and its volume will be expanded ().
①3 times, ②6 times, ③9 times, ④27 times.
Third, the judge.
1. The total amount of money subscribed to Little Torch is directly proportional to the number of copies ordered. ( )
2. Legends should be used to make composite bar charts. ( )
3. The scale is 1 cm on the map, which means the actual distance is 20km. ( )
There are 55 students in the class, the ratio of male to female is 5:6, so there are 30 boys in this class. ( )。
5. The lateral area of two cylinders is equal, and their bottom perimeters are equal. ( )
6. In the proportion, the product of two external terms is 10, one internal term is 5, and the other internal term is also 5. ( )
7 =B, then a and b are inversely proportional. ( )
8. The circumference and diameter of a circle must be in direct proportion. ( )
Fourth, the solution ratio.
= : = :χ =
40:χ=2.5: 15 :χ=5: 16 : =20:χ