### Understanding Quadrilaterals - Revision Notes

CBSE Class 8 Mathematics

Revision Notes

Chapter – 3

Understanding Quadrilaterals

Revision Notes

Chapter – 3

Understanding Quadrilaterals

- Parallelogram: A quadrilateral with each pair of opposite sides parallel.

(1) Opposite sides are equal.

(2) Opposite angles are equal.

(3) Diagonals bisect one another. - Rhombus: A parallelogram with sides of equal length.

(1) All the properties of a parallelogram.

(2) Diagonals are perpendicular to each other. - Rectangle: A parallelogram with a right angle.

(1) All the properties of a parallelogram.

(2) Each of the angles is a right angle.

(3) Diagonals are equal. - Square: A rectangle with sides of equal length.

(1) All the properties of a parallelogram, rhombus and a rectangle. - Kite: A quadrilateral with exactly two pairs of equal consecutive sides

(1) The diagonals are perpendicular to one another

(2) One of the diagonals bisects the other.

(3) In the figure but . - Trapezium: A quadrilateral having exactly one pair of parallel sides.
- Diagonal: A simple closed curve made up of only line segments. A line segment connecting two non-consecutive vertices of a polygon is called diagonal.
- Convex : The measure of each angle is less than .
- Concave: The measure of at least one angle is more than
- Quadrilateral: Polygon having four sides.
- Element of quadrilateral:

(i) Sides: Line segments joining the points.

(ii) Vertices: Point of intersection of two consecutive sides.

(iii) Opposite sides: Two sides of a quadrilateral having no common end point.

(iv) Opposite Angles: Two angles of a quadrilateral not having a common arm.

(v) Diagonals: Line segment obtained by joining the opposite vertices.

(vi) Adjacent Angles: Two angles of a quadrilateral having a common arm.

(vii) Adjacent Sides: Two sides of a quadrilateral having a common end point.