Now we look at 4 sided polygons, which are called quadrilaterals, A quadrilateral can be named as a Square, rectangle, rhombus, trapezium, kite or a Parallelogram based on the different properties of the quadrilaterals. If all the sides of the quadrilateral are equal, then it is a regular quadrilateral and is a special type quadrilateral. It can be a square or a Rhombus, depending upon the angles measure of the figure, which we will study in other sessions. In a quadrilateral we have a closed figure formed by joining 4 sides of equal or unequal lengths. All the quadrilaterals have 4 sides, 4 vertices and so it has 4 angles. If the quadrilaterals are in form of the square or Rectangle, then it has all angles equal (90 degrees each).
The sum of all the angles of the four sided figures (called quadrilaterals) is 360 degrees. We observe that the quadrilateral is the figure which is formed by the joining of two Triangles. When we join any two diagonals of the quadrilateral, it forms 2 triangles. Moreover we know that the sum of angles of the triangle is 180 degrees and so two triangles form 360 degrees.
A kite is also a special type of quadrilateral, where we find that the opposite sides are not equal, but the pair of the adjacent sides of the kite is always equal, so we do not have the horizontal line of Symmetry, in kite as we have in the quadrilaterals square and the rectangles. A kite always has one vertical line of symmetry.
Now we look at a parallelogram, which is he tilted form of the rectangle, but does not have a line of symmetry.
This is all about special quadrilateral.