NCERT Solutions
Class 9 - Mathematics - Chapter 8: QUADRILATERALS
EXERCISE 8.2

Question. 1

ABCD is a quadrilateral in which P, Q, R and S are mid-points of the sides AB, BC, CD and DA respectively. AC is a diagonal. Show that:

(i) SR ∥ AC and SR = 1/2 AC

(ii) PQ = SR

(iii) PQRS is a parallelogram.

Question. 2

ABCD is a rhombus and P, Q, R and S are the mid-points of the sides AB, BC, CD and DA respectively. Show that the quadrilateral PQRS is a rectangle.

Answer:

Show PQRS is a parallelogram. Also show PQ ∥ AC and PS ∥ BD. So, ∠P = 90°.

Question. 3

ABCD is a rectangle and P, Q, R and S are mid-points of the sides AB, BC, CD and DA respectively. Show that the quadrilateral PQRS is a rhombus.

Question. 4

ABCD is a trapezium in which AB ∥ DC, BD is a diagonal and E is the mid-point of AD. A line is drawn through E parallel to AB intersecting BC at F. Show that F is the mid-point of BC.

Question. 5

In a parallelogram ABCD, E and F are the mid-points of sides AB and CD respectively. Show that the line segments AF and EC trisect the diagonal BD.

Answer:

AECF is a parallelogram. So, AF ∥ CE, etc.

Question. 6

ABC is a triangle right angled at C. A line through the mid-point M of hypotenuse AB and parallel to BC intersects AC at D. Show that:

(i) D is the mid-point of AC

(ii) MD ⟂ AC

(iii) CM = MA = 1/2 AB

NCERT Solutions Class 9 – Mathematics – Chapter 8: QUADRILATERALS – EXERCISE 8.2 | Detailed Answers