1, HL is the HL theorem in mathematics. The hypotenuse and the right-angled side correspond to the coincidence of two right-angled triangles.

2.HL theorem is a theorem to prove the congruence of two right triangles. It is proved that the right side and hypotenuse of two right triangles are equivalent.

3. The judgment theorem is that if the hypotenuses of two right-angled triangles and a right-angled side are equal, then the congruence of these two right-angled triangles (abbreviated as HL) is a special judgment method, which can be converted into ASA, which can confirm SSA.