Junior High School Math! First Aid First Aid! Junior high school math problems, fast

Let the radius r of the large circle be r, and the small garden is r

So the arc length of the great circle = the circumference of the minor circle.

r*pie*2*1 4=r*pie*2

So r=4r

Connect the square diagonally.

The length is 2a

Again, it is equal to r+r+ 2r

Because r=4r

So it is equal to 4r+r+ 2r=r(5+ 2).

Because r(5 + 2) = 2a

So r=2a (5+ 2).

There is a physical and chemical denominator.

a*(5√2-2)/21

Let the length of the bus bar be l and the radius of the bottom surface be r

2*pi*r=2*pi*l 4 Because the sector angle = 90, l = 4r According to the geometric relationship, the root number 2*a=l+r + the root number 2*r=(5 + the root number 2)*r

Therefore r = root number 2 * a (5 + root number 2).

(5 times the root number under 2)-2]a

The radius of the land area is r, and the radius of the arc length is r

If the arc length is equal to the perimeter of the land area, r=4r can be obtained

Then there is the Pythagorean theorem, which gives the square of 2a = the square of (r + r + r times the root number of 2).

Results can be obtained.

This question is not difficult, maybe you usually have less contact with the bits and pieces of life, to know more about life, it will be helpful for everything! The answer to this question is as follows:

1. Positive direction.

2. Explain that the shelf life is 20 days or months, with a plus sign on the top and a horizontal sign on the bottom, indicating that the temperature of the food is stored in the range of minus 3 degrees to minus 3 degrees.

3. +19 (note that the first layer of the surface is the 0th layer), -5,124, indicating that the change of the commodity** (whether it is an increase or a decrease) is in the range of 10% of the original price.

Hope it helps!

Professional Answers).

*4* (square decimeter.)

2. The length of the cuboid box is 30 cm, the width is 20 cm, and the height is 5 cm, so the volume is 30 * 20 * 5 = 3000 cubic cm = 3000 ml.

(cubic decimeters.)

40-10) * (30-10) = 600 cubic centimeters.

Hope it helps!

Do df perpendicular to bc to f

Because ab is the diameter, and ad, bc are tangents.

So it can be proved that the quadrilateral adfb is rectangular.

So bf=ad=x, df=ab=12, because da, de is tangent.

So de=ad=x

The same goes for ce=cb=y

So cd=ce+de=x+y

In the right triangle CDF df 2+cf 2=cd 212 2+(y-x) 2=(x+y) 2

Simplification yields xy=36

y=36/x

Because x,y is the length of the line segment.

So x>0, y>0

So the image is the part of the hyperbola in the first quadrant.

Connect OE, OD OC

From the tangent length theorem, ad=de=x

ec=bc=y

Easy angle doc = 90°

Let the radius be r, then the square of OC is equal to the square of r + the square of y od = the square of r + the square of x.

So the square of r + the square of x + the square of x + the square of y = the square of x + the square of y can be simplified.

Equilateral triangles are sensitive to percolation.

The precursor certificate EAF is fully equal to the FDCEF=FC, EFA= CFDBecause EFA+ AFC=60°, CFD+ AFC=60°. and ef=fc, so efc is an equilateral triangular bridge ridge.

Let bh be x, then hc=1000-x, according to the title, there is: ah=xac=2x (the right-angled side corresponding to 30° in the right-angled triangle is equal to half of the hypotenuse), in the triangle ahc:

x 2 + (1000-x) 2 = 4x 2 to solve the equation.

Author: nanrouzhen |Level 2 | 2010-11-24 21:55

1、x² -x+3

x-1 2) +11 4 (squared non-negative).

So (x-1 2) +11 4> = 11 42, x -2x-3

x-1）²-4

So the corresponding positions are equal.

m=1,k=-4

m+k=-3

3、-2x²+4x-6

2（x²-2x+3）

2[(x-1）²+2]

2(x-1）²-4

Because -2(x-1) <=0

So -2(x-1) -4<=-4

The maximum value is -4

=x^2-x+1/4+11/4

x-1/2)^2+11/4

Regardless of the value of x, (x-1 2) 2>0

i.e. (x-1 2) 2+11 4>11 4;

2. x² -2x-3

x^2-2x+1-4

x-1)^2-4

where: m=1, k=-4

m+k=1-4=-3 ;

3.-2x^2+4x-6

3-x)(2x-2)

When x=0, -2x 2+4x-6 =-6