Trapezoid that has at least one line of symmetry perpendicular to the bases.
- Its sides adjacent to the bases are congruent.
- It has two pairs of congruent adjacent angles.
- An isosceles trapezoid is symmetric about the perpendicular bisector to one of its bases.
- In an isosceles trapezoid, the sides adjacent to the bases are congruent.
This is an isosceles trapezoid: