 Hello and welcome to the session. In this session we will discuss kinds of quadrilaterals. Based on the nature of the sides or the angles of a quadrilateral we have different kinds of quadrilaterals. First kind of quadrilateral that we have is a trapezium. Let's discuss about the trapezium now. It is a quadrilateral with a pair of parallel sides. This figure A, B, C, D is a trapezium where we have A, B and C, D are the parallel sides. If the non-parallel sides of a trapezium are of equal length then it is an isosceles trapezium. Like if in this trapezium A, B, C, D, A, D is equal to B, C then we say that A, B, C, D is an isosceles trapezium. Next quadrilateral that we need to discuss is a kite. Let's see what is a kite. It is a quadrilateral in which there are exactly two distinct consecutive pairs of sides of equal length. It is basically a special type of a quadrilateral. Consider this figure A, B, C, D in which we have A, B is equal to A, D and B, C is equal to C, D. That is we have two distinct consecutive pairs of sides of equal length are there in this figure so A, B, C, D is a kite. Next we discuss parallelogram. It is a quadrilateral whose opposite sides are parallel. Consider this figure A, B, C, D. In this we have that A, B is parallel to C, D and A, D is parallel to B, C. That is we have the opposite sides are parallel so this A, B, C, D is a parallelogram. Now considering this figure we will discuss some elements of a parallelogram. Like a parallelogram has four sides and four angles, the sides A, B and D, C are the opposite sides. Then another pair of opposite sides are sides B, C and A, D are also opposite sides. Angle A and angle C are the opposite angles. Then angle B and angle D are also the opposite angles. Then the sides A, B and B, C are the adjacent sides and the sides B, C and C, D are also the adjacent sides. Adjacent sides are those in which one of the sides starts where the other ends. Like in A, B and B, C, A, B ends at B, side B, C starts at B. So we say A, B and B, C are the adjacent sides. In the same way we can find out other pairs of adjacent sides in this parallelogram. Angle A and angle B are the adjacent angles. Then angle B and angle C are also adjacent angles. That is these are the angles at the ends of same sides. In the same way we can find out other pairs of adjacent angles of this parallelogram, ABCD. We shall now discuss some properties of a parallelogram. Like the first one says the opposite sides of a parallelogram are of equal length. That is if you consider this parallelogram ABCD you say that AB is equal to CD and AD is equal to BC. Then the opposite angles of a parallelogram are of equal measure. That is angle A is equal to angle C and angle B is equal to angle D. Then the next property is the adjacent angles in a parallelogram are supplementary. That is we have angle A plus angle B is equal to 180 degrees. In the same way angle B plus angle C is equal to 180 degrees. Angle C plus angle D is equal to 180 degrees. And angle D plus angle A is 180 degrees. Now we have another property related to the diagonals of a parallelogram. It says that the diagonals of a parallelogram bisect each other. We know that the diagonals of a parallelogram are not of equal length. In this figure you can see that AC and VD are the diagonals. Now they intersect at the point O and we know that the diagonals bisect each other at point O. So we have that AO is equal to OC and BO is equal to OD. This complete session hope you have understood the kinds of quadrilaterals.