There are two equal isosceles right triangles on one side that are congruent

Wrong. The right-angled side of this triangle is equal to the hypotenuse of the other, and the corresponding is equal, not necessarily refers to the right-angled side to the right-angled side, and the hypotenuse to the hypotenuse, as long as one side of the two triangles is equal, the topic is satisfied. So the answer to your book is right!

That's right. Because the correspondence on one side is equal indicates that they are positional correspondence, of course they are congruent".

Congruence Let one triangle be abc and the other def

Because ABC is an isosceles triangle.

So ab=ac

And because def is an isosceles triangle.

So de=df

Because de=ab

So de=df=ab=ac

And because of ABC, def are both right triangles.

So in the RT triangle ABC and the RT triangle.

ab=deac=df

So rt triangle abc congruent rt triangle def

Narrative error. The right-angled side of this triangle is equal to the hypotenuse of the other, and the corresponding is equal, not necessarily referring to the waist to the waist, the bottom edge to the bottom edge, as long as one side of the two triangles is equal, the topic is satisfied.

True proposition. That's right.

The premise is an isosceles [right angle] triangle.

As long as one side is equal to each other, it is equivalent to three-sided equivalence.

Therefore, it is complete. If it's an isosceles triangle, it's a different story.

Wrong. It is not possible if the right-angled side of this triangle is equal to the hypotenuse of the other.

Not necessarily. It is possible that he is one of them with an equal waist.

It is also possible that one bottom is equal.

So: a base corresponds to an equal isosceles triangle congruence.

If one of the two isosceles triangles is equal to one waist, then there are two sides that correspond to each other.

Because of the isosceles triangle the two waists are equal.

And then there are two more bottom angles that are equal (equilateral-to-equisome), so they can be (sas) or.

aas）

There is one side that corresponds to an equal determinable congruence.

But it is not necessarily true that there are equal sides.

For example, if one waist is equal to the beveled edge of the other, it is not complete.

Because it can be obtained from the nature of the isosceles triangle: the two bottom angles of the isosceles triangle are equal, so the isosceles triangle must have two equal angles, so the answer is: the correct Li Zi sedan chair

Acute triangle.

Because an isosceles triangle must have two equal angles, and these two angles must be less than 90 degrees (because the triangle has only 180 degrees of inner angles).

Angles less than 90 degrees are acute angles, so acute angles are the correct answer.

Of course, right triangles can sometimes be used.

Two isosceles right triangles with equal hypotenuse are waiting.

Must be congruent. The three angles of an isosceles right triangle are 45 degrees, 45 degrees, and 90 degrees, and if the hypotenuse is equal, you can use the corner corner to get the congruence of the two triangles.

2) Intercept BM slowly on BC so that BM=HC

It is easy to prove that the triangle HCD is all equal to the triangle head Minna shape DMB

HD=DM is obtained, and then it is proved that the triangle DCG is equal to the triangle DGM

It's difficult, how many years ago.

I'd like to know, but it's just a similar question.

The two triangles in the diagram have one side corresponding to equal (ac=a'c') and the other two sides corresponding to parallel (ab a'b', bc b'c').

This triangle is obviously not equal to the hair.

It is possible that an obtuse triangle and an acute triangle also satisfy the above conditions, but they are not congruent.

c.Question analysis: A The waist is equal, one angle is 40°, if one is the top angle and the other is the bottom angle, the two triangles are not equal, so the option is wrong;

b Two equilateral triangles are not necessarily congruent, so the option is wrong;

c There are two isosceles triangles with an angle of 100° and equal bases congruence; The 100° angle can only be the top angle, so the bottom angle can be found to be 40°, and the congruence of the two triangles can be determined according to the ASA, so the option is correct;

d There is no clear correspondence, if one is the bottom edge and the other is the waist or one is the bottom angle and the other is the top angle, then the two isosceles triangles are not equal so choose BC