The correct matching of the abbreviation to its description is:
hl: a hypotenuse and a leg define congruence
la: a hypotenuse and an acute angle define congruence
ll: a leg and an acute angle define congruence
ha: two legs define congruence
These abbreviations are used in congruence statements for right triangles, which are statements that describe when two right triangles are congruent (i.e., have the same shape and size). In a right triangle, the sides are labeled with the letters "a," "b," and "c," where "a" and "b" are the legs of the triangle and "c" is the hypotenuse.
The congruence statements for right triangles use these labels to describe when two triangles are congruent. For example, the statement "ha" means that two right triangles are congruent if their legs (labeled "a" and "b") are of equal length. The statement "ll" means that two right triangles are congruent if one of their legs (labeled "a" or "b") and one of their acute angles (labeled "A" or "B") are of equal length and measure, respectively.
Similarly, the statement "la" means that two right triangles are congruent if their hypotenuses (labeled "c") and one of their acute angles (labeled "A" or "B") are of equal length and measure, respectively. And the statement "hl" means that two right triangles are congruent if their hypotenuses (labeled "c") and one of their legs (labeled "a" or "b") are of equal length.