A math problem, solved quickly, math problem, solved urgently

Extend a waist in the direction of the extension point, and make a perpendicular line through the bottom angle to the extension line, and the opposite side of the 30-degree angle in the right-angle triangle is half of the hypotenuse, so the perpendicular line segment is 5 cm, with the waist as the bottom, and the perpendicular line segment is high.

Cm.

You draw a reflection of the triangle along the bottom edge.

That is, a diamond shape with a side length of 10 and a top angle of 30 degrees is formed.

The area of the triangle is half of it.

10 * 5 times the root number 3 2 = 25 times the root number 3

I'll give you a hint, you do the math yourself!

Take one bottom corner as the vertex to make the perpendicular line segment of the other waist.

We can construct a right-angled triangle with an angle of 30 degrees.

Then the area of the triangle can be calculated by using the waist as the base edge and the length of the perpendicular segment as the height.

Let the triangle be abc and the apex angle is a and make the high cd on the side of ba, because the base is 15 degrees, then the apex angle is 150 degrees, and the complementary angle of the apex angle is 30 degrees.

The triangle cda is a right-angled triangle, knowing one side, knowing a special angle of 30 degrees, you can find that the side length of the cd is 5cm

Then the area of the triangular row is ba*cd*1 2=10*5*1 2=25

To make an isosceles triangle at its height, set the height to h and the bottom to a

sin15 degrees = H10

h = 10sin15 degrees.

Cos15 degrees = (1 2)A10

a = 20cos15 degrees.

s (1 2) base x height.

1/2)axh

1 2) x20cos15 degrees x10sin15 degrees.

100cos15 degrees sin15 degrees.

What grade are you in? Don't say you're in the third year of junior high school or higher?

Make an extension of the triangle at the waist

You don't need to count, just look at the requirements to know the final form (a+b)*(a+c)*(b+c)=0;This must satisfy that there are at least 2 opposite numbers in a, b, and c. Of course, mathematics must pay attention to calculations and ideas, so let's start from the above ideas and transform 1 a+1 b+1 c=1 (a+b+c), that is, factor decomposition after general division; Advance score: a 2 + a 2b + b 2c + b 2a + c 2b + c 2a + 2abc = 0....

1);a(ab+ac+b^2+bc)+c(ab+ac+b^2+bc)=0...2);

a+c)(ab+ac+b^2+bc)=0...3);

a+c)(a+b)(b+c)=0...4);And so it was.

Neither the counter-argument nor the assumption of ABC is reciprocal.

12:30 Let t be the travel time of A: 40t-60(t-1)=10 to solve t

Not very clear. Since it cannot be less than 10 km. And how do you let the car pass?

That's a problematic question!

Solution: Knowing from the question.

x1+x2=-1／a x1×x2=-1

So in x1 and x2, there is a positive and a negative.

Also Nian Dan Rock x1 x2

x1 Late core 0 x2 0

x1|+|x2|=x1-x2=4

x1＋x2）²=x1-x2）²＋4x1×x2（-1／a）²=4²＋4×（－1）

i.e. 1 a =16-4

a²=1／12

a = root number 1 12 or a = - root number 1 12

x1+x2=-1 a x1*x2=-1<0 and x1>x2

So x1> shouting wheel 0 x2<0 so Zheng Xin x1-x2=4

From the above equation, the reed chain can be found.

That's it. c

When you make an appointment, you need to check whether it is equal to 0

A 2-b 2=0, a=b, can not be reduced, the equation is still satisfied, so we get another case, the triangle abc may be an isosceles triangle, so the correct conclusion is: abc is an isosceles or right triangle.

（8*8 + =

The root number is approximately equal to centimeters.

1 inch = centimeter.

After conversion, it is about inches.

The screen size is the size of the diagonal, which is generally inches.

Calculation method: 8*8+ result is about, converted to inches is about inches.

Take the width of the mobile phone as the side length, bc=, then ab=

ad=ao=

Cut four triangles and put them together.

4bc=6，bc=

Side length 2=height.

Triangle height = isosceles triangle side length = (

What the hell are you going to do?

Total work Planned power – Total work Actual efficiency.

8000 320-8000 400=5, completed five days in advance.