Quadrilaterals Class 9 Formula
In this page we have given list of formula for Quadrilaterals Class 9. Hope this Quadrilaterals Class 9 Formula will help students to quickly solve Quadrilaterals math.
A) Definition: – Quadrilateral is a polygon of four sides. It is a figure which is formed by joining four points such that no three points are collinear
Properties of Quadrilateral:
1) A quadrilateral has four sides, four angles and four vertices.
2) The sum of the angles of a quadrilateral is 360°.
3) A diagonal of a parallelogram divides it into two congruent triangles.
4) In a parallelogram Opposite sides are equal and Opposite angles are equal.
5) A quadrilateral is a parallelogram.
B) Types of Quadrilaterals
1.) TRAPEZIUM: A quadrilateral with at least one pair of opposite sides parallel is called trapezium.
2.) PARALLELOGRAM: A quadrilateral with both pairs of opposite sides parallel is called parallelograms.
3.) RHOMBUS: A parallelogram having all sides equal is called rhombus.
4.) RECTANGLE: A parallelogram with one angle a right angle is called rectangle.
5.) SQUARE: A parallelogram having all sides equal and one angle a right angle is called square.
6.) KITE: A quadrilateral with two pairs of adjacent sides equal, but opposite sides are not parallel, is kite.
C) Key Points:
1) Square, Rectangle and rhombus are all parallelogram.
2) Kite is not a parallelogram.
3) A trapezium is not a parallelogram.
4) A parallelogram is a trapezium.
5) A square is rectangle and also rhombus.
6) A rectangle or a rhombus is not a square.
D) Properties:
1) Diagonals of a rectangle bisect each other and are equal.
2) Diagonals of a rhombus bisect each other at right angles.
3) Diagonals of a square bisect each other at right angles and are equal.
4) Quadrilateral formed by joining the mid-points of the sides of a quadrilateral, in order, is a parallelogram
5) Quadrilateral formed by joining the mid-points of the sides if a rhombus is a rectangle.
E) Theorem:
MIDPOINT THEOREM states that: The line segment joining the mid-points of two sides of a triangle is parallel to the third side.
The line drawn through the mid-point of one side of a triangle, parallel to another sides bisects the third side.
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