Is a square a trapezoid?

(I assume everyone's got the same definition of 'square'.) The obvious (to me) definition of 'trapezoid' is "quadrilateral with a pair of parallel sides". read more

No, a square is not a trapezoid! The definition of a square does not comply with the definition of a trapezoid. The definition of a trapezoid is a quadrilateral (a closed plane figure with 4 sides) with exactly one pair of parallel sides. read more

A tangential trapezoid is a trapezoid that has an incircle. A Saccheri quadrilateral is similar to a trapezoid in the hyperbolic plane, with two adjacent right angles, while it is a rectangle in the Euclidean plane. read more