As shown in the figure, in △ ABC, ∠ a = 40 ° and ∠ ABC = ∠ ACB, the middle vertical line (please draw with a compass and ruler) on the side of AB intersects AC at D and ab at e, connecting BD, (1) Explain why △ ade is congruent with △ BDE (2) Finding the degree of ∠ DBC

(1) Since e is the intersection of the middle perpendicular of AB, then E is the midpoint of AB, so AE = be
The middle vertical line is perpendicular to AB, so ∠ AED = ∠ bed = 90 °
Both △ ade and △ BDE have the same edge
To sum up, AE = be ∠ AED = be ed = ed corner
So △ ade is congruent with △ BDE
（2）∠a=40°,∠abc=∠acb
Because the inner angle of the triangle is 180 degrees, then ∠ ABC = ∠ ACB = 70 degrees
And because △ ade is congruent with △ BDE
Then ∠ a = ∠ EBD = 40 °
The degree of ∠ ABC = ∠ abd + DBC
The degree of 70 ° = 40 ° + DBC
So the degree of ∠ DBC = 30 degree
It's simple.

(1) In △ ABC, just use a compass and a ruler without scale to make the vertical bisectors of edges AB and ac. they intersect at point O and connect OA, OB and OC
(2) Complete the following reasoning process:
Because point O is on the vertical bisector of line AB,
So () = () reason:
Similarly () = ()
So () = ()
So point O is on the middle perpendicular of line BC
Therefore, the distance from the intersection of the vertical bisectors on both sides of the triangle to the triangle () is equal

Because point O is on the vertical bisector of line AB,
So (AO) = (Bo) reason: the distance from the point on the vertical bisector of the line segment to the point at both ends is equal
The same as AOCO
So (Bo) = (CO)
So the point O is on the middle perpendicular of the line BC. Reason: if the distance from one point to the two ends of the line is equal, then this point must be on the middle perpendicular of the line BC
Therefore, the distance from the intersection of the vertical bisectors on both sides of the triangle to the triangle (each vertex) is equal

In △ ABC, ab = AC, and the acute angle obtained by the intersection of the vertical bisector of AB and the line where AC is located is 50 °, then ∠ B is equal to______ ．

According to ∠ A is acute angle and obtuse angle in △ ABC, it can be divided into two cases: ① when ∠ A is acute angle, the acute angle obtained by the intersection of the vertical bisector of ∵ AB and the line where AC is located is 50 °, and ∵ a = 40 °, and ∵ B = 180 °− A2 = 180 °− 40 ° 2 = 70 °; ② when ∵ A is obtuse angle, the acute angle obtained by the intersection of the vertical bisector of ∵ AB and the line where AC is located is 50 °, and ∵ 1 = 40 °, and ∵ BAC = 140 Therefore, the answer is: 70 ° or 20 °

In △ ABC, ab = AC, and the acute angle obtained by the intersection of the vertical bisector of AB and the line where AC is located is 50 °, then ∠ B is equal to______ ．

According to ∠ a as acute angle and obtuse angle in △ ABC, it can be divided into two cases: ① when ∠ A is acute angle, the acute angle obtained by the intersection of the vertical bisector of ∵ AB and the straight line of AC is 50 °, and ∵ a = 40 °, and ∵ B = 180 − A2 = 180 − 40 ° 2 = 70 °. ② when ∵ A is obtuse angle, the vertical bisector of ∵ AB and the straight line of AC are

0.2x power > 1 / 25

x> 1 / radical 5, X

If (2x-1) 0 power = 1, then what is the value range of X?

x≠1/2

-What's the fourth power of 5? What does it mean

Read as negative 5 to the fourth power
It is the opposite of the fourth power of 5

What is the meaning of the third power of 4

-4 & # 179; denotes the opposite number of the third power of 4

The fractional power of a number

The fractional power of a number is equal to the numerator power of the number, followed by the denominator power
8^(2/3)=³√(8²)=³√64=4

As shown in the figure, in △ ABC, ∠ a = 40 ° and ∠ ABC = ∠ ACB, the middle vertical line (please draw with a compass and ruler) on the side of AB intersects AC at D and ab at e, connecting BD, (1) Explain why △ ade is congruent with △ BDE (2) Finding the degree of ∠ DBC