You have learnt how to draw triangles in Class VII. We require three measurements (of sides and angles) to draw a unique triangle. Since three measurements were enough to draw a triangle, a natural question arises whether four measurements would be sufficient to draw a unique four sided closed figure, namely, a quadrilateral.
We shall learn how to construct a unique quadrilateral given the following
1. When four sides and one diagonal are given.
2.When two diagonals and three sides are given.
3. When two adjacent sides and three angles are given.
4. When three sides and two included angles are given.
5. When other special properties are known.
4.3 Some Special Cases To draw a quadrilateral, we used 5 measurements in our work. Is there any quadrilateral which can be drawn with less number of available measurements? The following examples examine such special cases.