only 1 pair of parallel sides

It seems like you're referring to a geometric shape that has only one pair of parallel sides. This description typically fits a trapezoid (or trapezium in some regions). ### Known Conditions: - The shape has one pair of parallel sides. ### Explanation: 1. **Definition of a Trapezoid**: A trapezoid is a four-sided figure (quadrilateral) with at least one pair of parallel sides. The parallel sides are often referred to as the "bases," while the other two sides are called the "legs." 2. **Properties of a Trapezoid**: - The angles between the legs and the bases can vary. - The lengths of the legs can be equal (in which case it is an isosceles trapezoid) or unequal. - The area of a trapezoid can be calculated using the formula: \[ A = \frac{(b_1 + b_2) \cdot h}{2} \] where \( b_1 \) and \( b_2 \) are the lengths of the parallel sides, and \( h \) is the height (the perpendicular distance between the bases). 3. **Types of Trapezoids**: - **Isosceles Trapezoid**: The legs are of equal length, and the angles at each base are equal. - **Right Trapezoid**: At least two angles are right angles. If you have a specific question or need further details about trapezoids or related concepts, please let me know!