5 practical questions 100 correct good ones are extra points!!

1) "The tip of the minute hand "traveled the distance:

60（14-8）*2*pi*8= cm

2) The maximum circle diameter is the width of the rectangular paper: 12 cm, and the radius is 6 cm

20*12-pi*6^2 = cm^2

3) The area of the gravel road is the area of the ring

pi*(8+1) 2-pi*8 2 = m 24) The circumference of a circular grain hoard is: = m, so the radius of a circular grain hoard is: r = m The area of a circular grain hoard:

pi*r 2= m 25) to make the area of the round table the largest, should make the 4 pieces of the swing form a square, the remaining one can be placed at will, the radius of the round table is: r=, the circumference of the round table: 2*pi*r=2* m

Number of nails: round 19

So the number of copper nails is at least 19.

1.From 8 a.m. to 2 p.m., six hours passed, turning 360 degrees in an hour.

Then 2*8**6=96 cm.

2.The diameter of the circle is 12

20*12-(12 2) 2 =240-36 square centimeters.

3.(8+1) 2 -8 2 =17 square meters.

Rice. Square metre.

m = 120 cm 20 cm = 6 = 19

Children, it is not good to be able to post on the Internet but not to calculate the circumference and area of a circle.

Study hard.

Good luck dayup!

Child, I'm sinking to the bottom, so don't you take the roll call...

1. 2 o'clock in the afternoon is 14 o'clock, and the time difference is 14-8=6, that is, the tip of the minute hand has gone 6 times.

2* Despise plagiarism.

2. Cut out the largest circle, then its diameter is up to 12, and the area of the circle is a rectangular area of 20*12=240

Remaining Area = Despise plagiarism.

3. The total area of road + flower bed is (8 + 1) * (8 + 1) * flower bed area is 8 * 8 *

The area of the road is two area differences, and plagiarism is despised.

4. The circumference of the circle is.

Perimeter = 2 * Radius The radius is.

Area = Despise plagiarism.

5. According to the theme, only the long, wide wooden board can make the largest round table, so that the diameter of the circle is, the circumference of the circle is m = cm, and a copper nail is nailed every 20 cm, and a total of at least 19 nails are needed to despise plagiarism.

1 6 * 2 pie r = 96 pie.

2 20 * 12 - faction r = 240-36 faction.

3 factions * 9 squared - faction * 8 squared = 17 factions.

4 Pier r= s=pie r = pie.

5 rectangles that can be spelled out, s=2 pies, r=pies, plus a nail at the starting point, so 20 are used.

1) This batch of coal was actually burned for 52 days.

2)4x3-4-4x3x1/4=5

There are 5 liters left. 3) There are x fronts in this batch of zero sheds.

x/2+3x/7+450=5x/4

x=1400

4) Master Wang Yanqing processes and prepares x parts per hour.

11x=6x+50x6

x=605) met the bus for x kilometers.

x-9x/10=9x2

x=180

(1) This is an engineering application problem. The characteristic of engineering application problems is that unit 1 is generally represented by "1".

Explain that A's work efficiency is one-fifth. Then B's work efficiency is one-half, and putting one-fifth + one-half is equal to the work efficiency of two people in one day. Take their productivity in one day by 2, and you equals two days of productivity.

Their 2-day work is a fraction of the size of the project.

2) Then put the unit one, which is the project. Subtract what they did in these two days. If you divide the rest by A's work efficiency, it will be a few days.

Am I clear enough? Thank you! Hope it helps!

Are you in the sixth grade?

（1） 1/5=1/5 1/6=1/6 （1/5+1/6）*2=22/30

2) 1-22 30=8 30 8 30 1 6=8 5 (days).

Copy it, count yourself lucky, our Olympiad class just talked about engineering problems yesterday.

If teams A and B work together for 2 days, (1 5 + 1 6) * 2 = 11 15 will be used to complete the project

Next, it will be done by A alone, and it will take (1-11 15) 1 5=4 3 days.

（1） 2/5+2/6=17/30

13 6 (Balance.)

Answer: 17 30 completed this work. After 2 days of joint work between teams A and B, the next thing to be done by A alone will take 13 to 6 days to complete.

1；The efficacy of A is 1 5 per day, and the efficacy of B is 1 6 per day

2；(1-11 30) 1 5=19 6 days.

Set Xiaoqing is x years old this year, and his father is y years old, and there are:

y=3x；y+13=2(x+13);

3x+13=2x+26;

x=13;y=39；

So Xiaoqing is 13 years old this year, and his father is 39 years old this year.

She Xiaoqing is x years old this year, and her father is y years old this year.

3x=y2(x+13)=y+13

3x=y2x+13=y

x=13y=39

This year, Xiaoqing is x years old, and his father is y years old.

3x=y2（x+13)=y+13

The solution is x=13 and y=39

Have fun.

Solution: Let's say Xiaoqing is x years old this year, and Xiaoqing's father is a few years old.

y=3x ⑴ y+13=2（x+13）⑵

Substituting into , we get 3x+13=2x+26

3x-2x=26-13

x=13 Substituting x=13 gives y=39

I won't write the answer.

Father X, Xiaoqing Y

x=3yx+13=2（y+13）

Solve.

Let Xiaoqing's current age be x and his father's age be y, then:

y=3xy+13=2(x+13)

Solution: x=13

y=39

Question pinch? Or can't you see it on my phone?

1) 5 square centimeters.

1 4) r -(1 handicap 2) r 2) =51 4) r -(1 8)) r absolute=51 8)) r =5

1 and slip 2) 10 -(1 2) 20 x=57x=5, take.

Answer: 1) The area of the circle of 1 4 is 5 square centimeters.

Then: the area of the circle is 20 square centimeters.

So: 20 = p * r 2, then: r 2 = 20 The diameter of the p-semicircle r=r

So: the front shed of the semicircle is (p*r 2) 2

p*(1/4)r^2)/2=5/2

2) The area of A is 57 square centimeters larger than that of B.

Therefore, the area of the semicircle minus the area of the triangle is also 57, i.e., 1 2*p*10 2-1 2*20x=57 solution: x=

Where: p denotes pi.