CBSE Class 9 Maths Quadrilaterals
Types and Angle Sum PropertyA quadrilateral is a closed figure of four sides.
Sum of the angles of a quadrilateral is 360 degree.
Different types of quadrilaterals are: Parallelogram with opposite sides parallel and equal in length Square, rhombus and rectangle all are parallelograms with special properties.
Trapezium and kite are other quadrilaterals.
Parallelograms: Basic PropertiesA diagonal of a parallelogram divides it into two congruent triangles.
In parallelogram opposite sides are equal.
A quadrilateral is parallelogram if its opposite sides are equal.
Angle Relations in ParallelogramA quadrilateral is a parallelogram if both the pair of opposite sides are parallel to each other.
In a parallelogram both pairs of opposite angles are equal in measure.
A quadrilateral is a parallelogram if both pairs of opposite angles are equal in measure.
Parallelograms: Diagonal PropertiesDiagonals of a parallelogram bisect each other. If the diagonals of a quadrilateral bisect each other then it's a parallelogram.
Diagonals of a rectangle are equal to each other.Diagonals of a square and rhombus are perpendicular bisectors of each other.
If the diagonal of a parallelogram bisect one of its angle then it also bisects the other angle.
Mid-Point TheoremThe line segment joining the mid points of any two sides of a triangle is parallel to the third side and is half of its length.
A line through the Mid Point of a side of a triangle parallel to another side bisects the third side.
If the intercepts made by a transversal on one side of a pair of parallel lines are equal then they are equal on the other side as well.