Proof: there are two equal triangles corresponding to the bisector of two angles and one of them

Proof: there are two equal triangles corresponding to the bisector of two angles and one of them

If two corners are equal, three corners are equal, so only one side is equal
There are two triangles ABC and a1b1c1, the angles of corresponding letters are equal, ad and a1d1 are bisectors of angles, and ad = a1d1, then
In the triangle abd and a1b1d1, angle B and angle B1 are equal, and angle DAB = angle d1a1b1
So angle ADB = angle a1d1b1, and ad = a1d1, so triangle abd and triangle a1b1d1 are congruent, so AB = A1B1
So the proposition is proved

Given that the perimeter of two triangles is equal, and the two angles are equal, the congruence of the two triangles is proved

According to the fact that the two angles of a triangle are equal, the two triangles are similar
The corresponding sides of similar triangles are in positive proportion, and the ratio of corresponding sides is equal to the ratio of perimeter,
Because the perimeter is equal, the corresponding edges are equal,
Then the two triangles are congruent

The area of a classroom is 86.94 square meters, which is paved with 0.5-meter-long square tiles. How many tiles do you need

Square tile area = 0.5 × 0.5 = 0.25 M2
86.94 / 0.25 tiles needed = 347.76
So at least 348 yuan is needed

Customs of 56 nationalities

1. Tibetans are mainly distributed in Tibet, and the rest are in Qinghai, Gansu, Sichuan, Yunnan and other places. Tibetans believe in Lamaism. Offering "hada" is the most common and ceremonious etiquette of Tibetans to their guests. The longer and wider the hada is, the more ceremonious the etiquette is

Find the value of sin20 + cos50 + sin20cos50,

sin^2 20+cos^2 50+sin20cos50
=(sin20+cos50)^2-sin20cos50
=(sin20+sin40)^2-sin20cos50
=(2sin30*cos(-10))^2-sin20cos50
=cos10^2-sin20cos50
=(1+cos20)/2-1/2*[sin70+sin(-30)]
=1/2+1/2*cos20-1/2*[cos20+sin(-30)]
=1/2+1/4
=3/4

In the handicraft class, Mr. Tang asked the students to cut an isosceles right triangle (as shown in the figure) from one corner of a rectangular paper. What is the area of the remaining part?

15 × 11 - (11-3) × (11-3) △ 2, = 165-8 × 8 △ 2, = 165-32 = 133 (square centimeter). A: the area of the rest is 133 square centimeter

What is the law of resistance in parallel circuit?

Let the resistance of each branch in parallel circuit be R1, R2, R3, RN, and the current of main circuit be r, then:
1/R=1/R1+1/R2+1/R3+...+1/Rn

Given the function f (x) = log21 + x1 − X. (I) write out the domain of definition of function; parity of function (II) according to the definition of monotonicity of function, prove that function f (x) is an increasing function

(I) to make f (x) meaningful, that is, 1 + x1 − x > 0, the domain of F (x) is (- 1,1). (II) since the domain of F (x) is (- 1,1), and f (- x) = log21 − X1 + X = log2 (1 + x1 − x) − 1 = - log21 + x1 − x = - f (x), f (x) is an odd function

The area of a square is 24 square centimeters, and the area of the largest circle in it is 18.84 square centimeters

Yes

The isosceles triangle ABC is divided into two isosceles triangles according to the line AB = AC ∠ a = 36 ° passing through a vertex
Please draw a picture and mark the angle at least 4 different ways

Three angles, half of 36, 72, 72, 72, 36, approximate triangle, draw by yourself