2. In 1 ~ 15, the ratio of all even sums to all odd sums is (7: 8), and the ratio of all prime sums to all synthetic sums is (1: 3).
3、0.8=(4) :(5) == 8÷( 10)=(80)%
4. The volume of the cone is 76 cubic centimeters, and the bottom area is 19 square centimeters. The height of this cone is (12) cm.
5. If 4a=5b, then a: b = (5) :(4).
6. The commonly used statistical charts we have learned are (bar chart), (pie chart) and (line chart).
7. In a right triangle, the ratio of two acute angles is 1: 2, which are (30) degrees and (60) degrees respectively.
8. You can choose four numbers from the divisor of 12 to form a ratio. Please write two groups with different proportions: (1: 3 = 4: 12) and (2: 4 = 6: 12).
9. If the distance between Party A and Party B is 4.8 cm on the map of 1: 500000, the actual distance between the two places is (240) km.
10. The radius of the bottom surface of the cylinder is 2 cm, and the side surface is exactly square. The volume of a cylinder is (16π? ) cubic centimeters.
Second, judge. (5 points)
1, 3 meters and 1 meter are equal. ( × )
2. The former term of the ratio is definite, and the latter term is inversely proportional to the ratio. ( √ )
3. All even numbers are composite numbers. ( × )
4. cuboids and cylinders with equal bottoms and heights have equal volumes. ( √ )
5. Remove the 0 after the decimal point, and the size of the decimal point remains unchanged. ( × )
Third, choose one. (Fill in the serial number of the correct answer on the horizontal line, 5 points)
1. Dissolve 4g sugar in 100g water, and the ratio of sugar to sugar water is (b).
A 1:25、B 1:26、C 1:4%
2. A barrel of salad oil weighs 12kg. After pouring out half, the barrel weighs 7 kilograms. If 1kg oil is sold in 8.6 yuan, this barrel of oil can be sold (b).
A 43 yuan B 86 yuan C 103.2 yuan.
3. Area and radius of a circle (A).
A is proportional, B is inversely proportional, and C is not proportional.
4, kilometer scale, rewritten as a digital scale is ().
a 1:30 B 1:900000 C 1:3000000D
5. The following statement is correct (C).
A means that two ratios are equal, which is called positive ratio. Two numbers b are coprime and have no common divisor.
The numerator of c is fixed, and the fractional value is inversely proportional to the denominator. The volume of a cone is equal to the volume of a cylinder.
3. Solve the equation. (9 points)
2X+3×0.9=24.7
2X+2.7=24.7
2X=22
X= 1 1
0.3 :x= :5 1
=0.5
4, column comprehensive formula or equation solution. (6 points)
(1) A number is less than 3.2 times of 65438+0.6 times of 4.5. Find this number.
4.5× 1.6-3.2=4
This number is 4.
(2) What is the difference between 6 divided by 6 and 6 divided by 6?