The volume of a cylinder is 3.6 cubic decimeters, and that of a cone is () cubic decimeters

The volume of a cylinder is 3.6 cubic decimeters, and that of a cone is () cubic decimeters

The volume of a cylinder is 3.6 cubic decimeters, and that of a cone is (1.2) cubic decimeters
A cylinder and a cone of equal base and height with equal base circumference and equal height
The volume of a cone is one third of that of a cylinder

1. The diameter of the bottom of a cone is equal to its height, and its circumference is 28.26 cm. What is the volume of the cone in cubic cm?
2. For a conical iron block, the diameter of the bottom is 6cm and the height is 10cm. What is the volume of this iron block?

1. Diameter: 28.26 △ 3.14 = 9 radius: 9 △ 2 = 4.5 volume: 1 / 3 × 3.14 × 4.5 × 4.5 × 9 = 190.755 cm3
2. Radius: 6 △ 2 = 3 volume: 1 / 3 × 3.14 × 3 × 3 × 10 = 94.2 cubic centimeter

A cone with a height of 10 decimeters and a volume of 12.56 cubic decimeters is 3.14 cubic decimeters more than that of a cone with the same height as the ground. What is the height of the cone?

The base area of the cone is s square decimeter
1/3×s×10=12.56
s=3.768
(12.56-3.14) / (1 / 3 × 3.768) = 7.5 (decimeter)

Xiao Ming carelessly forgot the decimal point of a two digit decimal in his homework. The number of integers he got was 35.64 more than that of the decimal from yuan, so he calculated the original decimal
By the way, add 100 points

Forget the decimal point of two decimal places, and the new number is 100 times of the original one
99 times larger than the original decimal
The original decimal is 35.64 △ 99 = 0.36

Party A and Party B are facing each other from ab at the same time. For the first time, they meet at C, which is 40km away from point A. after that, they continue to return to each other's starting place to see the supplement
For the second time, I met at D, which is 9km away from A. how many kilometers is the distance between a and B? The more detailed, the better

Distance between two places of AB: (40x3-9) / (1 + 0.5) = 64 (km)

What is the basis of rational number classification
Rational numbers can be divided into negative numbers, positive numbers and zero three categories. There are also seed methods, which can be divided into two categories: integer and fraction. What is the basis of these two different classification methods? Please give some advice from experts in logarithm theory. Thank you

To understand rational numbers, we must know real numbers and irrational numbers
All realistic numbers are called real numbers, which can be divided into irrational numbers and rational numbers
Irrational number is the real number of irrational number. It can't be written as the ratio of two integers, which is what we call infinite acyclic decimal
Rational numbers refer to all real numbers that can be reduced to fractions
Rational numbers can be divided into fractions and integers according to the simplest mathematical expressions
According to our definition, it can be divided into negative number, 0 and positive number

A and B trains leave 1080 kilometers apart from each other at the same time. They run in opposite directions and meet each other in 8 hours. A train runs 70 kilometers per hour, and B train runs how much per hour

70*8=560
1080-560=520
520/8=65

The average of a set of data 25, 27, 30, x, 29 is 28, then x is ()

It's all upstairs
30=28+2
27=28-1
25=28-3
30=28+2
29=28+1
5-4=1
So x = 28 + 1 = 29

A car drove 140 kilometers from a to B in the first two hours. At this speed, it will take three hours to reach B. how long is the highway between a and B? Fast, now, now
Using proportional solutions

140 / 2 = 70 (km / h)
70 * (2 + 3) = 350 (km)
A: the highway between a and B is 350 kilometers long

In a certain year of the 20th century, the square of my age is the number of A.D. in that year. In a certain year of the 21st century, what is my age

10 years old
One year in the 20th century to one year in the 21st century is a century, that is, a hundred years, so you are 10 years old