100 Bounty Points! My sister s fourth grade math problem requires detailed answers .

The answer is 48, and the area will not change.

48 square centimeters.

No matter how you cut it, the area will not change.

First, the original area is calculated using the parallelogram formula, 8x6=48 (cm 2).

Because it is a rectangle made of cut-and-pieces, the area does not change, only the perimeter.

In this way, the areas should be equal.

From this, it can be concluded that the area of the rectangle = the area of the parallelogram = 48 cm2

48 square centimeters.

Because the height of the parallelogram is made, the height is cut along the height, and the resulting triangle is added to the other side of the parallelogram, which is a rectangle, so the area of the even rectangle is the area of the parallelogram.

s=6*8=48

Good. The area of this rectangle is also 6*8=48 (square centimeters).

Because parallelograms are special rectangles.

So they have different circumferences and shapes, but the area is the same.

Because it is cut into a rectangle, the area of the rectangle should be equal to the area of the parallelogram, so you can find the area of the parallelogram.

8*6=48 cm.

Because after shearing along its height, it is put together into a rectangle, and does not increase or decrease the value, so: 6*8 is equal to 48

6*8=48 square centimeters.

The length of the rectangle is 8 and the width is 6

Cut off the triangular edge of the parallelogram and put it on the other corner. turned into a rectangle. The bottom is equivalent to the length and height of the rectangle, which is equivalent to its width. So the equation is: 8 times 6 to get 48

The area of the parallelogram is 48, and it is also 48 after the cut

At 48 square centimeters, he is a special rectangle.

48。Equal to the parallelogram area.

In fact, it is 8*6 because the hypotenuse of the parallelogram is cut out of a triangle and put together on the other side to form a rectangle.

48 can't be wrong, no matter how you cut the area, it won't change....

24.After cutting it, you have to put it back together, don't you? So the area is not still the area of the original triangle, think about it and figure it out, I hope it will help you!

48!If you don't dye it, you don't have hair! My sophomore in high school.

How the area will not change.

s square = s parallelogram. Bottom * high.

48(cm^2)

The quadrilateral is a shape, the bottom edge is 8 centimeters high, and it is 6 centimeters, and it is three-dimensional.

The area of the parallelogram remains unchanged even if it is tangent.

1. The speed of going down the river is the speed of the water + the still water speed of the ship, and the counter-current is the still water speed of the ship - the water speed, so the sum of the speed of the downstream and counter-current is twice the still water speed of the ship, that is, the speed of the ship in the still water is 65 km h, and the water velocity is 15 km h.

2. The speed of the ship is 20 kilometers when going downstream, so the still water speed of the ship is 18 kilometers per hour, the speed of the ship against the current is 16 kilometers per hour, and the speed of 80 kilometers takes 5 hours.

3. The simple way is to find the speed from A to B and B to A respectively (that is, the speed of the ship when going downstream and against the current), and then calculate it according to the method of the first question.

Or it can be understood in this way, the water is accelerating at the speed of water, and the water is decelerating by the resistance of water, so the water speed is twice as fast as the water speed is against the water, and the water is 5 hours slower than the water with the water, so the water flows from A to B in only 10 hours, so the water speed is kilometers and hours.

4. The speed of the ship is 30 kilometers when it is downstream, so it is 120 kilometers from A to B, and the speed of the ship is 20 kilometers when it is against the water, so it takes 6 hours.

Boat = (50 + 80) 2 = 65 km/h, V water = 80-65 = 15 km/h; Boat = (40-2*2) 2=18 km/h, time=80 (18-2)=5 hours; Boat = ((208 8) + (208 13)) 2 = 21 km/h, v water = (208 8)-21 = 4 km/h; Distance between two places = (25 + 5) * 4 = 120 km, time = 120 (25-5) = 6 hours;

1。The velocity of the water flow 15 The velocity of the boat in still water is 652. 80 km in 5 hours.

3。The speed of the water is 5 km h.

4。It returns the same way it came, which takes 6 hours.

Kid, you gave a title and forgot to post the title

Except for the bottom, all exposed surfaces should be painted, right? ++.

10 1=10 times [10 saws in total].

10 1 = 11 paragraphs [11 paragraphs in total].

11 40 = 440 cm.

440 centimeters = meters.

A: It's a meter long from wood.

10 1 = 10 (times).

10 1 = 11 (segment).

11 40 = 440 cm = m.

A: It's a meter long from wood.

x <=, i.e. 4< x <=

At least more than 4 meters and up to meters.

Because the title does not give a reason, whether it is just used up to cut into a small piece of rice).

According to the principle of one knife and two sections, it took ten minutes to saw a total of eleven sections, that is.

10 1=10 times [10 saws in total].

10 1 = 11 paragraphs [11 paragraphs in total].

11 40 = 440 cm.

440 centimeters = meters.

A: It's a meter long from wood.

It can also be written as (10 1+1) 40 = 440 cm = m.

10 1=10 times [Calculate how many times you saw in total?] A total of 10 saws] 10 1 = 11 segments [11 segments in total].

11 40 = 440 cm.

440 centimeters = metre units.

A: It's a meter long from wood.

(40 1 0 +40) 100 = m 10 times for a total of 11 segments.

Do you know the meaning of *, why can't it be used?

1. Recursive equation operation (as simple as it can be).

1) 256-159-241+544 Solution: original formula = (256+544)-(159+241)=800-400=400

2) 25 (376-85 4) solution: original formula = 25 (94 4-84 4) = (25 4) (94-84) = 100 10 = 1000

3) 10600 [4 (100-87)] solution: original formula = 10600 (4 13) = 10600 52 = 2650 13

4) 159 78-78-78 58 Solution: Original formula = 78 (159-1-58) = 78 100 = 7800

5) [108+(125-17) 9] 20 Solution: Original formula = (108+108 9) 20=(108+12) 20=120 20=2400

6) 25 36 7-3600 solution: original formula = 36 (25 7-100) = 36 (175-100) = 36 75 = (9 3) (4 25) = 27 100 = 2700

2. Practical questions.

1.The canteen used to burn 20 cubic meters of gas per day, but after the equipment was improved, it saved 4 cubic meters per day. How many days can I use gas for 40 days?

Solution: (20 40) (20-4) = [(4 4) (5 10)] 16 = 50 days.

2.To make 1,650 parts, Master Wang has to do it for 30 days alone. Master Li can make 55 in a day. If this batch of parts is made by two people together, how many days can it be completed?

Solution: 1650 (1650 30+55)=1650 (55+55)=1650 110=15 days.

3.The tree planting team planted 1,285 trees this year, 215 lessons less than last year's 2 times.

Solution: (1285+215) 2+1285=1500 2+1285=750+1285=2035 trees.

1. 1) Original formula = 256 + 544 - (159 + 241) = 800 - 400 = 400

2) Original formula = 25 (376-340) = 25 36 = 100 * 9 = 900

3) Original formula = 10600 [4 13] = 106 25 13 = 2650 13 = 203 + 11 13

4) Original formula = 78 * (159-1-58) = 7800

5) Original formula = (108 + 108 9) 20 = 120 * 20 = 2400

6) Original formula = 25 * 4 * 9 * 7-3600 = 100 * 63-3600 = 2700

Second, day 2Master Wang every day = 1650 30 = 55, and the two of them do it together = 1650 (55 + 55) = 15 days.

3.Last year = (1285 + 215) 2 = 750, two years total = 1285 + 750 = 2035 trees.

These questions of the landlord are very simple, as long as you are careful, you can quickly complete the answer, and the standard answer is as follows:

1. Recursive equation operation (as simple as it can be).

1) Original formula = 544 + 256 - (159 + 241) = 800 - 400 = 400

2) Original formula = 25x(94x4-85x4) = 25x4(94-85) = 100x9 = 900

3) Original formula = (4x2650) (4x13) = 2650 13 = 203 + 11 13

4) Original formula = 78x (159-1-58) = 78x100 = 7800

5) Original formula = (108 + 12) x 20 = 120 x 20 = 2400

6) Original formula = 25x36x7-25x36x4 = 25x36 (7-4) = 900x3 = 2700

2. Practical questions.

1) Analysis: The total amount of gas is 20x40 = 800 cubic meters, and the daily gas consumption is 20-4 = 16 cubic meters after the improvement of the equipment, so the gas can be used after the improvement of the equipment (20x40) (20-4) = 800 16 = 50 days.

2) Analysis: Master Wang makes 1650 30 = 55 parts a day, and Wang and Li make 55 + 55 = 110 parts a day, so 1650 parts, Wang and Li do 1650 (1650 30 + 55) = 1650 110 = 15 days to finish.

3) Analysis: Last year, we planted (1285+215) 2=750 trees, so we planted a total of (1285+215) 2+1285=750+1285=2035 trees in two years.

It's not easy to play by hand, it's ......

If the landlord doesn't adopt it, I'm sorry for me, .........

If you have any other questions or ask for help, I will help you as soon as possible.

A black dot represents the number 1 in the third digit from right to left, a triangle represents the number 1 in the second digit from right to left, a pentagram represents the number 1 on the first digit from right to left, so: choose b

Pick b hundred is a solid circle.

The ten digits are triangles.

The single digit is the star.

Option B first looks at the black solid circle, which represents 1, and 1 represents 1, then 352 first 3 must be 3 black solid circles, which can exclude c and dThe hints given by the comparison can then be inferred that the triangle is in the middle. Finally, select B.

Personally, I think I choose B

The black circle represents the hundreds, the triangle represents the tens digits, and the pentagram represents the single digits.

And then they are, and the number is a few corresponding figures, so choose B

According to examples, a black circle represents a hundred, a triangle represents a ten, and a five-pointed star represents a single digit. So 352 should be 3 circles, 5 triangles, 2 pentagrams. Hope to adopt, thank you!

As you can see from the hint, the first symbol black dot represents the first number, a black dot represents one, the second triangle represents the second number, a triangle represents one, the third polygon represents the third number, and each polygon represents one of the third digits, so 352 is three black dots, five triangles, two polygons, choose b

100ml cups are poured into 30ml cups, 30ml cups are poured into 70ml cups; 100ml cups are poured into 30ml cups, 30ml cups are poured into 70ml cups;

At this time, there is 40ml of water in a 100ml cup and 60ml of water in a 70ml cup.

Pour 100ml cup full of 30ml cup, pour 30ml cup into 70ml cup to make 70ml cup full of water;

At this time, there is 10ml of water in a 100ml cup, 70ml in a 70ml cup with water, and 20ml in a 30ml cup with water.

Pour 70ml cup of water into 100ml cup, pour 30ml cup of water into 70ml cup, then 100ml cup with water 80ml, 70ml cup with water 20ml, 30ml cup with water 0ml

100ml cups are poured into 30ml cups, 30ml cups are poured into 70ml cups;

At this time, 100ml has 50ml of water, and 70ml has 50ml of water.