Hello!
This is a trapezoid. It is a quadrilateral with one pair of parallel sides while other sides are non-parallel. Here, the opposite angles are alternate, that is, they have together 180°.
Isosceles trapezoid
An isosceles trapezoid is a trapezoid with congruent base angles and congruent non-parallel sides. Here, the base angles are the same.
The line segment joining the midpoints of the parallel sides is perpendicular to the bases and the diagonals are the same in length.
Good luck:)