definition of quadrilaterals,basic equality for quadrilaterals, angle sum property.

2. Quadrilateral – The word ‘quad’ means four and the word ‘lateral’ means
sides.
- It is a figure bounded by four line segments such that
no three of them are parallel to each other
- It has four sides, vertices, and angles
SOME IMPORTANT DEFINITIONS:-
a) Adjacent sides- also known as consecutive sides
- two sides of quadrilateral with common vertex
b) Opposite sides- two sides of quadrilateral with no common end- point
c) Adjacent angles- also known as consecutive angles
- two angles of a quadrilateral with common arm
d) Opposite angles- two angles of a quadrilateral with no common arm

3. Types of Quadrilaterals
Trapezium Kite
Rhombus Square
Parallelogram Rectangle

4. Let us discuss about various kinds of quadrilaterals briefly:-
TRAPEZIUM A quadrilateral with one pair of parallel sides
ISOSCELES TRAPEZIUM  A trapezium with non parallel sides as equal
TRAPEZIUM ISOSCELES TRAPEZIUM

5. PARALLELOGRAM  A quadrilateral with both pairs of opposite sides equal
RHOMBUS  A parallelogram with all sides equal

6. RECTANGLE  A parallelogram whose each angle is right angle
SQUARE  A rectangle with pair of adjacent sides equal

7. KITE  A quadrilateral with two pairs of equal adjacent sides and unequal
opposite sides

8. Let us discuss about various types of quadrilaterals in detail !!!
*RECTANGLE  opposite sides are parallel and equal
 all angles are right angles
 diagonals are equal
 diagonals bisect each other
*SQUARE  all sides are equal
 all angles are right angles
 opposite sides are parallel
 diagonals are equal
 diagonals bisect each other at right angles
 diagonals are perpendicular to each other
*RHOMBUS  opposite sides are parallel
 all sides are equal
 opposite angles are equal
 diagonals bisect each other
 diagonals are perpendicular to each other

9. *KITE two pairs of equal adjacent sides
*PARALLELOGRAM  opposite sides are equal
 opposite angles are equal
 diagonals bisect each other
 diagonals divide it into two congruent triangles
 bisect of any two consecutive angles intersect at right
angle
 its angle bisectors form a rectangle
*TRAPEZIUM  one pair of opposite sides are parallel
(Isosceles Trapezium has non- parallel sides equal to each other)

10. ANGLE SUM PROPERTY OF A QUADRILATERAL
This property states that sum of four angles of a quadrilateral is 360.
A B
C D
PROOF: IN ABD and ACD sum of angles =
180*+180*=360* [ angle sum property of a triangle ]
Hence, proved.

11. THANK YOU
BY- RADHIKA GUPTA