⁦The trapezium, its midline, a circumscribed quadrilateral and the area of a trapezium⁩

⁦In the Ukrainian programme this is Grade 8 geometry⁩, §1: ⁦item 8⁩ "⁦The trapezium⁩", ⁦item 10⁩ "⁦Circumscribed and inscribed circles of a quadrilateral⁩" ⁦and item 23⁩ "⁦The area of a trapezium⁩".

A شبه منحرف ⁦has exactly one pair of parallel sides (as in the Ukrainian books)⁩. ⁦The parallel sides are the bases, the others are the legs⁩. ⁦In an isosceles trapezium the legs are equal, the angles at a base are equal and the diagonals are equal⁩. ⁦The midline joins the midpoints of the legs, is parallel to the bases and equals half their sum⁩.

⁦A circle can be inscribed in a convex quadrilateral if and only if the sums of opposite sides are equal⁩: AB + CD = BC + AD.

⁦The area of a trapezium is S = a + b٢·h, where h is the height, not the leg⁩.