The bottom radius of a section of cylindrical wood is 20cm, and the height is 2m. How much is the surface area increased by sawing this section of wood into two cylinders of the same size from the middle? Note: the units are different

The bottom radius of a section of cylindrical wood is 20cm, and the height is 2m. How much is the surface area increased by sawing this section of wood into two cylinders of the same size from the middle? Note: the units are different

14 × 20 & # 178; × 2 = 2512 square centimeter
A: the surface area has increased by 2512 square centimeters

The bottom radius of a section of cylindrical wood is 20cm, and the height is 2m. How much is the surface area increased by sawing this section of wood into two cylinders of the same size from the middle

Add two bottom areas,
Increased
2×π×20×20
=800π
=2512 (CC)

The bottom radius of a section of cylindrical wood is 20 cm and the height is 2 M. how much has the surface area increased by sawing this section of wood from the middle into two sample size columns?

20 cm = 0.2 m, 3.14 × 0.22 × 2, = 3.14 × 0.04 × 2, = 0.2512 (M2). A: the surface area has increased by 0.2512 m2

The product of three consecutive even numbers is 192. What is the number of even numbers?
To solve the problem in detail, just answer not back, the answer I know

Let these three continuous even numbers be (2n-2), 2n. (2n + 2), then (2n-2) * 2n * (2n + 2) = 8 (n-1) * n * (n + 1) = 192 (n-1) * n * (n + 1) = 24. Simply and directly, we can see that n = 3 strictly needs to solve the univariate cubic equation (n-1) * n * (n + 1) = 24 (n ^ 2-1) n = 24N ^ 3-n-24 = 0n ^ 3-27-n + 3 = 0 (n-3) (n ^ 2 + 3N + 9) - (n-3) = 0 (n -

How many jin is a liter
Can you be more specific? How many jin is that liter? The density of water is different! Like oil

Liter and Jin are not the same unit of measurement. Liter is the unit of volume and Jin is the unit of weight
Weight = volume times specific gravity
For water, the specific gravity is 1kg / L, and the weight of a liter of water is 1kg, that is, 2kg. For water, the specific gravity is 7.8kg/l, and the weight of a liter of water is 7.8kg, that is, 15.6kg
One liter is equal to how many jin

All the formulas of the first day of Mathematics

It took me a lot of effort to get (a + b) + C = a + (B + C) A-B = a + (- b) (AB) C = a (BC) number of copies × number of copies = total number of copies ／ number of copies = total number of copies ／ number of copies = number of copies
2.1 times × times = several times △ 1 times = several times △ 1 times
3 speed × time = distance △ speed = time distance △ time = speed
4 unit price × quantity = total price / unit price = total quantity / quantity = unit price
5. Work efficiency × work time = total amount of work △ work efficiency = total amount of work time △ work time = work efficiency
6 addends + addends = sum - one addend = another addend
7 minus minus = difference minus minus minus minus = minus minus minus + minus = minus
8 factor × factor = product △ one factor = another factor
9 divisor / divisor = quotient divisor / quotient = divisor quotient × divisor = divisor
Primary school mathematics figure calculation formula
1 square C perimeter s area a side length
Perimeter = side length × 4 C = 4A
Area = side length × side length s = a × a
2. Cube V: Volume A: edge length
Surface area = edge length × edge length × 6 s surface = a × a × 6
Volume = edge length × edge length × edge length v = a × a × a
3 rectangle C perimeter s area a side length
Perimeter = (length + width) × 2 C = 2 (a + b)
Area = length × width s = ab
4 cuboid V: Volume s: Area A: length B: width H: height
Surface area (L × W + L × H + W × h) × 2 s = 2 (AB + ah + BH)
Volume = length × width × height v = ABH
5 triangle s area a bottom h height
Area = bottom × height △ 2 s = ah △ 2
Triangle height = area × 2 ／ bottom triangle bottom = area × 2 ／ height
6 parallelogram s area a bottom h height
Area = bottom × height s = ah
7 trapezoid s area a upper bottom B lower bottom h height
Area = (upper bottom + lower bottom) × height △ 2 s = (a + b) × h △ 2
8 circle s area C perimeter Π d = diameter r = radius
Perimeter = diameter ×Π = 2 ×Π × radius C = Πd = 2 Π R
Area = radius × radius ×Π (3.14)
9 cylinder V: Volume H: height s; bottom area R: bottom radius C: bottom perimeter
Side area = bottom perimeter × high surface area = side area + bottom area × 2
Volume = bottom area × height multiplied by volume = side area △ 2 × radius
10 cone V: Volume H: height s; bottom area R: bottom radius
Volume = bottom area × height △ 3 A / b = a * (1 / b) (B is not equal to 0) primary school mathematical figure calculation formula
1 square
C perimeter s area a side length
Perimeter = side length × 4
C=4a
Area = side length × side length
S=a×a
2 cube
5: Volume a: edge length
Surface area = edge length × edge length × 6
S table = a × a × 6
Volume = edge length × edge length × edge length
V=a×a×a
3 rectangle
C perimeter s area a side length
Perimeter = (length + width) × 2
C=2(a+b)
Area = length × width
S=ab
4 cuboid
5: Volume s: Area A: length B: width H: height
(1) Surface area (L × W + L × H + W × h) × 2
S=2(ab+ah+bh)
(2) Volume = length × width × height
V=abh
5 triangles
S area a bottom h height
Area = bottom × height △ 2
s=ah÷2
Triangle height = area × 2 △ bottom
Triangle bottom = area × 2 △ height
6 parallelogram
S area a bottom h height
Area = bottom × height
s=ah
7 trapezoid
S area a upper bottom B lower bottom h height
Area = (upper bottom + lower bottom) × height △ 2
s=(a+b)× h÷2
8 round
S area C perimeter Π d = diameter r = radius
(1) Perimeter = diameter ×Π = 2 ×Π× radius
C=∏d=2∏r
(2) Area = radius × radius ×Π
9 cylinder
v: Volume H: height s; bottom area R: bottom radius C: bottom perimeter
(1) Side area = perimeter of bottom surface × height
(2) Surface area = side area + bottom area × 2
(3) Volume = bottom area × height
(4) Volume = side area △ 2 × radius
10 cone
v: Volume H: height s; bottom area R: bottom radius
Volume = bottom area × height △ 3
Total number △ total number = average number multiplication and factorization
a2-b2=(a+b)(a-b) a3+b3=(a+b)(a2-ab+b2) a3-b3=(a-b(a2+ab+b2)
Trigonometric inequality
|a+b|≤|a|+|b| |a-b|≤|a|+|b| |a|≤b-b≤a≤b
|a-b|≥|a|-|b| -|a|≤a≤|a|
The relationship between solution root and coefficient of quadratic equation with one variable
-b+√(b2-4ac)/2a -b-√(b2-4ac)/2a
X1 + x2 = - B / a X1 * x2 = C / A
Discriminant
B2-4ac = 0 note: the equation has two equal real roots
B2-4ac > 0 note: the equation has two unequal real roots
b2-4ac0
Parabolic standard equation y2 = 2px y2 = - 2px x2 = 2PY x2 = - 2PY
Side area of straight prism s = C * h side area of oblique prism s = C '* h
Side area of pyramid s = 1 / 2C * h'side area of pyramid s = 1 / 2 (c + C ') H'
The area of the side of the cone s = 1 / 2 (c + C ') l = pi (R + R) l the surface area of the ball s = 4Pi * R2
Cylinder side area s = C * H = 2pi * h cone side area s = 1 / 2 * c * l = pi * r * l
The arc length formula L = a * r a is the arc number of the center angle R > 0 and the sector area formula s = 1 / 2 * L * r
Cone volume formula v = 1 / 3 * s * h cone volume formula v = 1 / 3 * pi * r2h
Volume of oblique prism v = s'L note: where s' is the area of straight section and l is the length of side edge
Cylinder volume formula v = s * h cylinder v = pi * r2h to be continued·····

10-4 M = () micron 1 nm = () 1 / 1 meter the diameter of a kind of cell in human body is 1 micron, () the head to tail connection of such cell can reach 1 micron
millimeter

10-4m = (100) micron
1 nm = (10 ^ 9) th of a meter
The diameter of a cell in the human body is 1 micron, and (1000) cells can be connected up to 1 millimeter
1 μ M = 10 ^ - 6M
1nm = 10 ^ - 9m
1 mm = 10 ^ - 3 M

How to convert density unit. Please give an example
How did 1g become 1000kg? Please explain

1g/cm^2=1000kg/m^3

1、2+4+6+8+…… +98+100=（ ）
2、A+4=B B+4=C A+B+C=120
A=（ ） B=（ ） C=（ ）

1、2+4+6+8+…… +98+100=102×25＝2550
2、A+4=B B+4=C A+B+C=120
A=（36） B=（40） C=（44）

How to do 51.4 - (0.14 + 0.54) simple method

51.4-(0.14+0.54)=51.4-0.4-(0.14+0.14)=51-0.28=50.72