The classroom is very quiet, only the teacher is giving a lecture On New Year's day, our family went to the artificial lake park. In the afternoon, as soon as we entered the park, we saw boats wandering on the lake and heard people's laughter

The classroom is very quiet, only the teacher is giving a lecture On New Year's day, our family went to the artificial lake park. In the afternoon, as soon as we entered the park, we saw boats wandering on the lake and heard people's laughter

Delete "very quiet" or add "my classmates" before it

There was a lot of applause in the classroom

There was a big round of applause in the classroom

As soon as the teacher came, the classroom calmed down

Quiet to quiet

Square ABCD is above the straight line Mn, BC is on the straight line Mn, e is on BC, with AE as the edge, make square aefg above Mn. Connect FC and find the degree of FCN

45 degrees
It is easy to prove that Abe is similar to EFH, and it is also easy to prove that Abe is similar to ACF, so EFH = AFC

Simplify the ratio of 8 / 9 below. Who can help me?

4/5:8/9=(4×9):(5×8)=36:40=9:10

How to calculate this quadratic radical? 3 - √ 3 divided by √ 3-1

For the form of denominator a + √ B (a - √ B is similar), the numerator denominator is usually multiplied by a - √ B to eliminate the root sign
（3-√3）/（√3-1）
=[（3-√3）（√3+1）]/[（√3-1）（√3+1）]
=2√3/2
=√3

As shown in the figure, in rectangle ABCD, rectangle ebfg gets rectangle hmnd through translation change. Points e, F, N and H are on the edge of rectangle ABCD. If be = 3, BF = 4, 4S3 = S1 + S2, and the lengths of ah and AE are integers, then the area of blank part in the figure is
S3 is the shadow part

I don't know where the blank area in your figure refers to. I can only say AE = ah = 2. If you mean the area other than S1 / S2 / S3, it's 20

1. Programming: enter a positive integer m to determine whether M is prime
Programming: input positive integer m to judge whether M is prime
A prime number is a positive integer, which can not be divided by any other positive integer except 1 and itself
If M can be divisible by any integer in 2m-1, the cycle will be ended ahead of time, and I ≤ M-1; if M cannot be divisible by any integer in 2m-1, the value of I will be m after the last cycle, indicating that M has not been divisible by any integer in 2m-1, and M is a prime
(you can also use 2 to SQR (m) as divisor
[further exercise 1] when the number entered by the user is not a positive integer, a prompt is given and a new number is required
[further exercise 2] find all prime numbers from 1 to 1000 and display them in the list box
[further exercise 3] give any upper and lower limits (positive integers) and find all prime numbers between them

A cube pool, 1.5m long, which covers an area of () m and 178; and can hold () l water when it is full of water
The diameter of the bottom surface of a cylinder is 4dm and the height is 9dm. Cut it into the largest cone, and the volume of the cone is () DM & # 179;
The length and width of the expanded rectangle are 12.56cm and 4cm respectively. The volume of the cylindrical water pipe is () CM & # 179;

It is a cube pool with the edge length of 1.5m. The pool covers an area of (2.25) m and can hold (3375) l of water
1.5x1.5=2.25 1.5x1.5x1.5x1000=3375
The diameter of the bottom surface of a cylinder is 4dm and the height is 9dm. It is cut into the largest cone, and the volume of the cone is (37.68) DM & # 179;
Radius 4 △ 2 = 2
3.14×2²×9÷3=37.68
The length of the expanded rectangle is 12.56cm, the width is 4cm, and the volume of the cylindrical water pipe is (50.24) cm;
The length of the expanded rectangle is the perimeter of the cross section of the original water pipe, and the width is the height of the original water pipe
So the height of this cylindrical pipe is 4cm
The volume is 3.14 × (12.56 △ 2 π) & 178; X4 = 50.24

Divide a given circle into several equal parts, cut them along the radius, and put them together into a given rectangle. The perimeter of the rectangle is 24.84 cm. What's the area of the rectangle

24.84=2R+2πR
So r = 3
So the area of rectangle or circle is 28.26