Math problems about triangles Urgent, math problems triangles .

1.Intersection of angles bisector?? Does it refer to the intersection of two angular dividers in addition to right angles?

135° (45° is fine, because the two angles add up to 180°, I don't know if you mean the big angle or the small angle).

2.From the title, the angle b is equal to the angle c, so the isosceles triangle,

The conditions are not clear.

In ABC, A=1 2 B=1 2 C, then ABC is an isosceles triangle.

b=2∠ac=2∠a

a=180÷5=36°、∠b=72°、∠c=72°

Let the angle a be x degrees, the angle b=, and the angle c=

x+ degrees. x = 90 because angle b = angle c

So this is an isosceles triangle (equiangular to equilateral).

A: This is a right-angled isosceles triangle (acute triangle).

Untie; 1 The sum of the two corners is 90, and after both corners are divided, it is 45, so the other corner is 135

There is also a complement angle of 45, which is 135 or 45

2 Let b=2x, then c=2x, a=x

2x+x+2x=180, x=36, 2x=72 are isosceles triangles, acute triangles.

1. The bisector of two acute angles constitutes a 135° angle, and the bisector of right angles and the bisector of acute angles cannot be found.

2. Isosceles triangle.

Let's talk about the second question first, which is relatively simple, and it is obviously an isosceles triangle.

As for the first question, if you have only these conditions, you don't seem to be able to get exact degrees, because the degrees of these angles will change with the change of the other two acute angles of this RT triangle.

That's it.

or 452Right-angled isosceles triangle.

The sum of the three sides of the triangle is 108 cm

If the ratio of the lengths of the three sides is 3:4:5, find the side lengths of the three sides.

If the ratio of the length of the three sides is 3:4:2How many centimeters are each of the three sides? What kind of triangle is he?

If you know that one of the outer angles of an isosceles triangle is 150°, then its base angle is ( ).

The sum of the inner angles of the triangle ABC is 180 degrees, so the angle A = 1 2 Angle B = 1 2 Angle C, that is, the angle A = 45 degrees, the angle B = 45 degrees, and the angle C = 45 degrees, so the triangle ABC is an isosceles triangle.

1.Suppose the three angles are A, B, and are right angles. The angle bisector of angle A and angle C is angle d, then d + half of (b + c) =, so angle d = 135 may also be a complementary angle of 135 45

1. Which angle of the triangle has three angles?

2. The degrees of the three angles of the isosceles triangle are °

2.The triangle is an isosceles triangle.

This question is very similar to a question in the International Mathematical Olympiad. It's complicated, so I'll talk about the idea. I'm sure you understand.

Find ef=ac

Because S ebf = s abc and bc = bf, their heights are equal.

Because of the high equality, ebf= abc, according to the trigonometric function can be known bc=ab, so it is easy to get ebf abc

So ef=ac, feb=bac

Find fd=cd

It is easy to obtain ec=af, s ecd=s adf

Next, the same as above, that is, the area is the same, there is an equal side, and there is a congruence of two triangles with equal angles, which can be used directly in the middle of the test.

In summary, we can see that ab=be, ad=ed, so b and d fall on the middle vertical line of EA.

Once you understand it, you can ball ef=2fd

And the results came out. It was 32

The edge AC folds along the AD and coincides with the AE.

The corners of the two triangles are equal, and the triangles are congruent.

acd≌△aed

ae=ac=6

be=ab-ae=10-6=4

The bed is a right-angled triangle.

bed∽△bca

be/bc=de/ac

de=4×6/8=3

acd≌△aed

cd=ed=3

Fold past, triangle ACD and triangle AC'd are two identical triangles, hence ac'=ac=6, so bc'=10-6=4, set cd=c'd=x, then bc'=8-x, at this point you can build the equation, I won't say much about it, just look at the sketch I made......

The ratio of length is 2:3:2, and the side length is x, then 2x:

3x:2x, so 2x+3x+2x=42, so x=6, so the longest side is 18cm, and if you classify it by side, it should be an isosceles triangle.

42/（2+3+2）=6

6*3=18 The longest side is 18cm

6*2=12 12cm isosceles triangle on the other two sides.

As shown in the figure, the area of the triangle ABC is 3:4 to the area of the triangle ADE, and the area of the triangle ABF is 10 square centimeters larger than that of the triangle FDE.

Connect df,ac, s cdf=s acf (same base and equal height), s def=s ace=x

s△abc：s△ade=3:4

s△abc=s△acd

s△acd：s△ade=3:4

s△ade=s△acd+s△ace

s△ade=4x,s△acd=3x

From the area ratio of the triangle ABC and the triangle ADE, AB:DE 3:4 is obtained, so AB:CE is 3:1

So the triangle abf: triangle cef 9:1, s cef quarter x (convertible).

S triangle ABF nine-quarters x

By using the S triangle ABF S ace (can be replaced with S ace) 10 to get x 8

So the quadrilateral area is 48

a3=10°；an=80° divided by 2 to the nth power (expressed mathematically) According to the known conditions, the angle b + angle c = 100°, the angle acd = 80° + the angle b (1) For the triangle A1BC: angle A1 + B 2 + (C

S triangle ABF nine-quarters x

By using the S triangle ABF S ace (can be replaced with S ace) 10 to get x 8

So the quadrilateral area is 48

6a.Because they are all made up of equilateral triangles.

The circumference is 12a, which is a regular hexagon with a side length of 2a.

Method: Divide the regular 6 sides with a side length of 2a into 6 regular triangles with a side length of 2a, and then divide one of the triangles into 4 regular triangles with a side length.

A high school exam question, right?

Solution: Let the sides of the bottom two triangles be x and y respectively, and the column formula is as follows:

x+a+a=2y

x=y+a, x=4a, y=3a

Circumference = 2 * 4a + 2 * 3a + (4a + a) + (4a + a) + 2 * 3a = 30a

Landlord: Why don't you draw. I can't draw a picture either. I had to borrow a drawing from the third floor. I don't know if it's right or not. The picture drawn on the third floor is not the same as his own answer.

I'll try to do it as follows:

Let the two w-shaped sides below be x

The upper side is y long

The left side is z

The lower side length is W

The small side in the middle is a (known).

Yes. y=2x---1）

y-a=z---2）

z-a=w---3）

w-a=x---4）

1) +2) +3) +4) get:

2y-3a=3x (substitute y=2x).

4x-3a=3x

x=3ay=6a、z=5a、w=4a

Circumference = 2x + y + 2z + 2w = 6a + 6a + 10a + 8a = 30a

Solution: Select C

Because the sum of any two sides of a triangle is greater than the third side, and the side length must be positive, (a+b+c)>0

a+b-c）>0

a-b-c)=a-(b+c)<0

So m<0

Solution: In the triangle, there is a law of "the sum of the two sides is greater than the third side, and the difference between the two sides is less than the third side", because a, b, and c are the three sides of the triangle, so a, b, and c are all numbers greater than zero, m=(a+b+c)(a+b-c)(a-b-c), in a+b+c>0, a+b-c>0, a-b-c<0, so m=(a+b+c)(a+b-c)(a-b-c)<0, so the answer should be c

Choose C, the sum of the two sides of the triangle is greater than the third side.

The sum of the two sides is greater than the third side, determine c