Math problems help though the score is less.

1.A round drum-shaped iron drum without a lid with a diameter of 4 decimeters on the bottom surface, and 5 decimeters high.

1) How much sheet does it take to make this iron bucket? (Ignored at the interface) The bottom area of the bucket is.

4 2) (4 2) square decimeter.

The side area of the bucket is:

4 square decimeters.

Iron sheets are needed to make this iron bucket.

square decimeters. 2) If an iron bucket is filled with water 2 decimeters high, how many liters of water is there?

The bottom area of the bucket is:

4 2) (4 2) square decimeter.

There is water in the place. cubic decimeter liters.

How many kilograms does this cone weigh if you cut a round block of wood with a bottom circumference of centimeters and a height of 6 centimeters into the largest cone? (Each cubic centimeter of wood weighs about 5 grams.) The final number is kept to two decimal places).

The base radius of the cone is.

Centimeter. The volume of the cone is.

Cubic centimetre. This cone weighs about a lot.

g kilograms.

1) Find the surface area, the area of the bottom surface square decimeter.

The circumference of the bottom surface is decimeter.

The area of the side Bottom circumference * height square decimeters.

Therefore, a total of iron sheets are required for the bottom area, the side area, and the square decimeter.

The height of the water is 2 decimeters.

Therefore, the volume of water is: bottom surface area * water height cubic decimeter.

The conversion relationship between cubic decimeter and liter is:

1 cubic decimeter 1000 cubic centimeters 1000 milliliters 1 liter.

So 2 decimeters high water has liters

The base radius of the cone is.

The volume of a centimeter cone is.

Cubic centimetre. This cone weighs about a lot.

g kilograms.

.14x4 = decimeter.

square = square decimeter.

squared] multiplied by 2 = cubic decimeters = liters.

14x( multiplied by 6 = cubic centimeters.)

Cubic centimetre. g kilograms.

1) In fact, it is to find the surface area of the iron bucket with one less bottom surface.

square decimeter) 2) is the quality of the water It can also be understood that it is the volume of the iron bucket 2 decimeters high.

cubic decimeters) liters) Question 3: Your question data may be wrong The test questions will not come out like this at all.

From the level of the class's test scores, Xiao Ming carefully analyzed whether the difficulty of this exam was great, and Xiao Ming regressed or improved.

Let Xiao Ming understand that skipping breakfast in the morning will not have much impact on the performance of the exam.

Xiao Ming is not suitable for the new teacher, and other students may not be suitable either, no matter what kind of teacher is the mathematics teacher, all the students can achieve good results as long as they listen carefully and review and preview carefully.

1.Set up basketballs and bought x pcs.

42x+35(6-x)=231

7x+210=231

x=3, so 3 each for basketball and football.

2.The social science and technology category is group X.

5x+3(9-x)=37

2x=10x=5, so 5*5=25 people for technology.

Art 3 * (9-5) = 12 people.

If you buy x basketballs, you buy (6-x) footballs.

then there is 42x+35(6-x)=231

7x+210=231

x=3 so basketball bought 3 and football bought 3.

There are 3 basketballs and footballs, 25 science and technology, and 12 arts.

1、（42*6-231）/（42-35）=36-3=3

Do it in 6th grade ways, for example:

There are n chickens and rabbits in the cage, 8 heads on the top, 26 feet on the bottom, how many chickens and rabbits are there?

1.Solution: Set up basketballs and soccer balls to buy x each, (6-x) each.

42x+35(6-x)=231 42x+210-35x=231 7x=21 x=3 6-x=6-3=3 Answer: Basketball and football bought 3 and 3 respectively. 2.

Solution: Set up X groups and (9-x) groups for science and technology and art. 5x and 3 (9-x) people will participate in the science and technology category and 3 (9-x) people in the art category.

5x+3(9-x)=37 5x+27-3x=37 2x=10 x=5 5x=5*5=25 people 3(9-x)=3(9-5)=12 people Answer: 25 people and 12 people participated in science and technology and 12 people in art.

The area of the enclosed square is the same as that of an isosceles triangle and the circumference is the same, and the area of the circle is the largest, so the area enclosed in a semicircle is the largest, and the area of a square or isosceles right triangle is a little larger.

The area of the semicircle is.

Isosceles right triangle! 15,7 is the bottom edge. The area at this time is the largest, and the area is.

The corner of the wall is 90 degrees angle, and the fan area is the largest, this does not need to be verified, this is the law of middle school questions, and you may be asked to verify why the fan area is the largest in high school or college.

1.。15*km divided by hours.

2.。540-10*32=220 220 divided by 5=44.

3.。 1。。。i.e. x=10 2... x divided by x=4Solution: Set last year x only.

3x-8=25 A: Last year, there were 11 rabbits.

3x=33x=11

5.Equation: Solution: Let each black goldfish be x yuan Arithmetic: (divide by 6 = yuan) Answer: Each black goldfish yuan.

12*6x=

x = A: Each black goldfish dollar.

Note: lz, a divided by b = b divided by a, so division and division are not the same) choose me, tired for a long time, (no plagiarism).

1。Total distance 15 * one speed 157 Now the speed is the time it takes now.

157 hours.

1 Total distance: Multiple lines are kilometers per hour divided by 9 hours.

2 The first ten days were planted: 10x32=320 540-320=220 left The last five days: 220 divided by 5=44 The average of 44 trees was planted every day in the five days after answering.

3 (1)x=(68-24) divided by x=10 (2)x= (3)x=divided by 7=

4 The first method: assuming that a was raised last year ax3=25+8 solution a=11 A: I raised 11 last year.

The second method: (25+8) divided by 3=11 A...

5 Equation: Let each black goldfish a yuan 6xa + a = A...

Arithmetic: Divide by 6=

General: (Divide by 6=.)

**What percentage of the total number of boys and girls were represented at the opening ceremony of the Olympic Games?

Question 1: Ideas: Make two high intersections, and the third line is also high.

Proof : Let a(0,a),b(b,0),c(c,0), the slope of the straight ac = -a c

Straight line bh slope = c a

Linear bh equation: y=c a(x-b), intersection with y-axis h(0,-bc a).

Straight ch slope = (BC A) C = B A

Straight line ab slope = -a b

kab*kch=-1

ch⊥ab.

Question 2. Proof: If the straight line where the diameter of the circle ab is located is taken as the x-axis, and the center of the circle is used as the origin, you may wish to set the radius of the circle to 1, so the equation of the circle is.

x^2+y^2=1.

The coordinates of a and b are a(-1,0) and b(1,0).

Let p(x,y) be any point on the circle, then there is y2=1-x2The slope of the pa is, k1=y (x+1).

The slope of pb is, k2=y (x-1).

k1k2=y^2/(x^2-1)=(1-x^2)/(x^2-1)=-1

pa pb, apb is a right angle.

Question 3. Curve c is a circle: (x-1) 2+(y-1) 2 =1. Center of the circle c(1,1), radius = 1

Straight line l: x a +y b =1, if the straight line l is tangent to the circle, then:

c(1,1) to the straight line l distance = radius = |1/a +1/b -1|/√1/a^2+1/b^2)

ab(ab-2a-2b-2)=0 ==ab-2a-2b+2 =0

a-2)(b-2)=2 ..1)

P(x,y), x=a 2,y=b 2

1) (x-1)(y-1)=1/2，(x,y>1)。This is the trajectory equation.

Triangle AOB area s = ab 2

ab-2a-2b+2 =0 ==ab+2=2(a+b)>=4√(ab)

ab>=6+4√2

s>=3+2√2

The minimum value of the area = 3+2 2

Question 4. The chord intersects the ellipse at the midpoint of the a(x1,y1), b(x2,y2) strings p(x,y) x1+x2=2x, y1+y2=2y

b^2x1^2+a^2y1^2=a^2b^2...1)

b^2x2^2+a^2y2^2=a^2b^2...2)

When AB is not perpendicular to the x-axis, x1 ≠ x2

1)-(2)：b^2(x1-x2)2x+a^2(y1-y2)2y=0

y1-y2)/(x1-x2)=-4x/9y=y/(x-1) 4x^2+9y^2-4x=0

When AB is perpendicular to the x-axis, p is the point (1,0) satisfying 4x 2+9y 2-4x=0

Therefore, the trajectory equation for the midpoint of the strings is: 4x 2+9y 2-4x=0

4.Through the ellipse x square 9 + y square 4=1, the strings are introduced at a certain point (1, 0), and the trajectory equation for the midpoint of the strings is found.

Let the endpoint be a(x1,y1) and b(x2,y2) with m(x,y) at the midpoint and the slope be k

Then 2x=x1+x2,2y=y1+y2 x1 2 9+y1 2 4=1,x2 2 y2 2 4=1

Subtract the last two formulas to obtain: 2x(x1-x2) 9+2y(y1-y2) 4=0 shift term (y1-y2) (x1-x2)=-4x 9y=k

k=y (x-1) so -4x 9y=y (x-1) 9y 2+4x 2-4x=0

1、[12.56 2 + = (kg2 = (square decimeter).

(1 - 15%) 240 = 160 (yuan 8 -5) 201 (cubic centimeters).

Application Question 1

2*pi*r=

So r=2 then find the base area and the side area).

pi*r*r+l*h=kg.

6/25 = 100% = (24%) 500% 225 = 100% = (25%) 76/25 = 10000 = (304 7/125 = 1/1000 = (56) 2/13 = 52/52 x 8 52 4/3 = 12/x 12 9

10024 1005/1000 304/1,000 56/1,000.

x=8 x=9