If a trapezoid has one pair of congruent base angles, then it is (a trapezoid, isosceles trapezoid).

Answer 1

If a trapezoid has one pair of congruent base angles, then it is an isosceles trapezoid. This is because, in an isosceles trapezoid, the non-parallel sides (legs) are equal in length, and the base angles adjacent to each base are equal.