Introduction to Quadrilateral
In introduction to quadrilateral, we will learn the basics about the quadrilateral.
The word ‘quad’ means four and the word lateral means sides. Thus, a plane figure bounded by four line segments AB, BC, CD and DA is called a quadrilateral and is written as quad. ABCD.
i) A i) AB
ii) B ii) BC
iii) C iii) CD
iv) D iv) DA
i) ∠A i) AC
ii) ∠B ii) BD
On the basis of diagonals, there are two types of quadrilaterals.
In Convex quadrilateral , the diagonals intersect in the interior region and in Concave quadrilateral , one of the diagonal is in the exterior region .
Various Parts of Quadrilateral
1) Adjacent sides : Two sides of a quadrilateral are called adjacent sides, if they have a common end point.
According to the given diagram, the adjacent sides are
i) AB, BC
ii) BC, CD
iii) CD, DA
iv) DA, AB
2) Opposite sides : Two sides of a quadrilateral are called its opposite sides, if they do not have a common end point.
i) AB and CD
ii) AD and BC
are two pairs of opposite sides of the quadrilateral ABCD.
Diagonals : It is formed by the segment joined by the opposite vertices.
AC and BD are diagonals.
Adjacent angles : Two angles of a quadrilateral are called adjacent angles, if they have a common side as an arm.
i) ∠A , ∠B
ii) ∠B, ∠C
iii) ∠C , ∠D
iv) ∠D , ∠ A
are four adjacent angles.
Opposite angles : Two angles of a quadrilateral are called opposite angles which are not adjacent angles.
i) ∠A , ∠C
ii) ∠B , ∠D are two pairs of opposite angles of the quadrilateral ABCD.
• Introduction to Quadrilateral
• Types of Quadrilateral
• Properties of Quadrilateral
• Parallelogram and its Theorems
• Rectangle and its Theorems
• Square and its Theorems
• Rhombus and its Theorems
• Trapezoid (Trapezium)and its Theorems
• Kite and its Theorems
• Mid Point Theorem