Question

can anyone explain whole chapter of Quadrilateral class 9 ​

Answer 1

A quadrilateral is a closed figure obtained by joining four point (with no three points collinear) in an order. Every quadrilateral has : (i) Four vertices, (ii) Four sides, (iii) Four angles and (iv) Two diagonals.

1st Theorem- The diagonal divides the parallelogram into two congruent triangles. 2nd Theorem- The opposite side of a parallelogram are equal. 3rd Theorem- The quadrilaterals in which each pair of opposite sides are equal are called parallelogram. 4th Theorem- The opposite angles of a parallelogram are equal.