Теория:

  • Quadrilaterals which has two parallel sides are called Trapezium.
Trapece (ne vienādsānu).JPG
 
  • Parallel sides of Trapezium are called its bases. 
\(AD\) and \(BC\) — bases.
 
  • Sides, which are not parallel, is called lateral sides of Trapezium.
\(AB\) and \(CD\) — lateral sides of the Trapezium.
 
There are a few kinds of Trapezium most often we talk about acute and isosceles Trapezium.
Right Trapezium
 Trapece (taisnleņķa).JPG
Trapezium, which has one lateral side perpendicular to bases, is called a right Trapezium.
Isosceles Trapezium
 Trapece (vienādsānu).JPG
Trapezium, which has equal lateral sides, is called an isosceles Trapezium.
Properties of Trapezium
  •  Angle: The sum of angles in a trapezium-like other quadrilateral is 360°. So in a trapezium ABCD, ∠A+∠B+∠C+∠D =   360° 
  • Two angles on the same side are supplementary, that is the sum of the angles of two adjacent sides is equal to \(\)180°\(\)
  • Its diagonals bisect with each other.
  • The length of the mid-segment is equal to 1/2 the sum of the bases. In the above figure mid-segment= 1/2 (AB+CD)
  • In special cases of the isosceles trapezium, legs of the trapezium are congruent to each other. This means that despite being non-parallel, the measurement of both legs is equal.
     
    Trapece (ne vienādsānu) 2.JPG