FTCE General Knowledge Math Practice Test 2025 - Free Practice Questions and Study Guide

An isosceles trapezoid is defined by the property that it has exactly one pair of parallel sides, known as the bases, and the nonparallel sides, or legs, are congruent in length. This characteristic creates symmetry in the shape, which means the angles adjacent to each base are equal. The congruence of the nonparallel sides contributes to its classification as "isosceles," highlighting the balance and equality of those particular sides.

The other choices do not accurately describe the features of an isosceles trapezoid. For instance, having all sides equal in length refers to a rhombus rather than an isosceles trapezoid. Describing it as having only right angles suggests a rectangle, another distinct shape. Finally, stating it has no parallel sides contradicts the very definition of a trapezoid, which must have at least one pair of parallel sides. Thus, the identifying feature of congruent nonparallel sides distinctly characterizes an isosceles trapezoid.