If the __________ and a leg of one triangle are congruent to the hypotenuse and a __________ of another triangle, then the triangles are congruent by the HL theorem.

The HL theorem applies to right triangles when the hypotenuse and one leg of one triangle are congruent to the hypotenuse and one leg of another. So the blanks are “hypotenuse” and “leg,” making choice A correct.

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