to use this calculator you need to know the 4 sides of a trapezoid

lines bc and ad are parallel and are called bottom edge

lines ab and dc are called trapezoidal waist

lines ac and db are called diagonal

lines perpendicular to ad & bc are called trapezoids high。

the line parallel to ad & bc and between ab and dc is called trapezoidmidline

median line = (ad + bc) ÷ 2