It is known that: as shown in the figure, points B, C and D are on the same straight line, ∠ ACB = ∠ ECD = 60 °, AC = BC, EC = DC. Connect be and ad, intersect AC and CE at points m and N respectively. Verify: (1) ACD ≌ BCE; (2) cm = CN

It is known that: as shown in the figure, points B, C and D are on the same straight line, ∠ ACB = ∠ ECD = 60 °, AC = BC, EC = DC. Connect be and ad, intersect AC and CE at points m and N respectively. Verify: (1) ACD ≌ BCE; (2) cm = CN

The following results are proved: (1) in △ ACD and △ BCE, AC = BC ∠ ACD = ∠ bcecd = CE and ≌ ACD ≌ △ BCE (SAS); (2) B, C and D are on the same straight line, and ≌ BCD = 180 °

In △ ABC, B (2sinb + sinc) + C (2sinc + SINB) = 2asina, and SINB + sinc = 1, find the angles a, B, C

Because B (2sinb + sinc) + C (2sinc + SINB) = 2asina, so 2B2 + BC + 2c2 + BC = 2A2, so A2 = B2 + C2 + BC, because A2 = B2 + c2-2bc * cosa, so cosa = - 1 / 2, that is, a = 120 degrees, because SINB + Sina = 1, that is, SINB + sin (60 degrees - b) = 1sinb2 + sinc2 = 1, so B = 30 degrees, C = 30 degrees

In the triangle ABC, if B / C = 3 / 5, then (SINB + 2sinc) / sinc=
Such as the title

According to the sine theorem: B / SINB = C / sinc
That is: SINB / sinc = B / C = 3 / 5
(sinB+2sinC)/sinC
=sinB/sinc+2sinC/sinC
=3/5+2
=13/5

In △ ABC, if B / C = 3 / 5, then (SINB + 2sinc) / sinc=

b/c=3/5,sinB/sinC=3/5
sinB+2sinC)/sinC=(3+10)/5=13/5

In the triangle ABC, ab = 5, AC = 3, BC = 7, then the size of ∠ BAC is______ ．

∵ AB = C = 5, AC = b = 3, BC = a = 7, ∵ according to the cosine theorem: cos ∠ BAC = B2 + C2 − A2 & nbsp; 2BC = 9 + 25 − 4930 = - 12, ∵ BAC is the inner angle of triangle ABC, ∵ BAC = 2 π 3

Side length formula of right triangle
It is known that the lengths of the two right angles are 10.5m and 3M respectively. What is the length of the hypotenuse?
Please give the specific length of the hypotenuse is how many meters!

According to Pythagorean theorem, the square of 10.5 plus the square of 3 is equal to the square of the hypotenuse
So the length of the hypotenuse is about the square root of 12.2 (not an integer)

The proving process of right triangle side length formula
Why is the square of the length of the hypotenuse of a right triangle equal to the sum of the squares of the two right angles?
That is the proof process of Pythagorean theorem

[proof 1] (Mei wending's proof) make four congruent right triangles, let their two right angle sides be a and B respectively, and the length of hypotenuse side be c. put them together into a polygon as shown in the figure, so that D, e and F are on a straight line. The extension line of AC through C intersects DF at point P. ∵ D, e and F are on a straight line, and RT Δ GEF

How to calculate the base and high perimeter of isosceles right triangle?

How to calculate the base d, height h and perimeter Z of an isosceles right triangle
Z = (1 + root 2) d = 2 (1 + root 2) H

How to calculate the perimeter of a right triangle?
The bottom edge is 6cm and the other edge is 8cm. What's the perimeter?

Hypotenuse = root sign (square of 6 + square of 8) = 10
Perimeter = 6 + 8 + 10 = 24

How to calculate the perimeter of right triangle and equilateral triangle
The right triangle forms are 4.2 decimeters, 4.8 decimeters and 3.6 decimeters, and the equilateral forms are 4.4 decimeters and 5.6 decimeters,

Right angle 4.2 + 4.8 + 3.6 = 12.6
Equilateral or isosceles? Equilateral is 4.4 * 3 = 13.2 5.6 * 3 = 16.8 isosceles 4.4 * 2 + 5.6 = 14.4 or 5.6 * 2 + 4.4 = 15.6