NCERT Solutions
Class 9 Maths
Areas of Parallelograms and Triangles

Ex.9.2 Q.5
In the figure, PQRS and ABRS are parallelograms and X is
any point on side BR. Show that
(i) ar (PQRS) = ar (ABRS)
(ii) ar (AXS) = ar
Given: PQRS and ABRS are parallelograms and X is any point on side BR.
To prove:
(i) ar (PQRS) = ar (ABRS)
(ii) ar (AXS) =
(i) In ∆ASP and BRQ, we have,
∠SPA = ∠RQB
[Corresponding angles] ... (1)
∠PAS = ∠QBR
[Corresponding angles] ... (2)
So, ∠PSA = ∠QRB
[Angle sum property of a triangle] ... (3)
Also, PS = QR
[Opposite sides of the parallelogram PQRS] ... (4)
So, ∆ASP ≅ ∆BRQ
[ASA axiom, using (1), (3) and (4)]
Therefore, area of ∆PSA = area of ∆QRB
[Congruent figures have equal areas] ... (5)
Now, ar (PQRS) = ar (PSA) + ar (ASRQ)
= ar (QRB) + ar (ASRQ)
= ar (ABRS)
So, ar (PQRS) = ar (ABRS), Proved.
(ii) Now, ∆AXS and ||gm ABRS are on the same base AS
and between same parallels AS and BR
So, area of ∆AXS = area of
=> area of ∆AXS = area of
[Since ar (PQRS) = ar (ABRS]
=> ar of (AXS) = area of