Proof: △ ABC△ a "b" c "

Proof: ∫∠A = 180-∠B-∠C, ∠ A "= 180-∠ B"-∠ C ",∠A =∞

In △ABC and △ A "B" C ",∫A =∠A", AB = A "B", ∠B=∠B ",

∴△ABC≌△A"B"C"(ASA)

Corner method is one of the methods to prove triangle congruence.

Expand (the meaning of)

The methods to prove the congruence of triangles are:

① congruences of three groups of two triangles with equal sides (SSS or "edge" for short)

② There are two congruent triangles (SAS or "corner edges") with equal angles.

(3) Two triangles with two angles and their corresponding equilateral congruence (ASA or "angle").

(4) There are two angles and the opposite side of an angle corresponds to the congruence of two triangles (AAS or "corner edge").

⑤ The congruence conditions of right-angled triangles are as follows: the hypotenuse and right-angled side correspond to the congruence of two right-angled triangles (HL or "hypotenuse and right-angled side").