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Constructions

Question
CBSEENMA9002838

P and Q are any two points lying on the sides DC and AD respectively of a parallelogram ABCD. Show that ar(ΔAPB) = ar{ΔBQC).

Solution
Given: P and Q are any two points lying on the sides DC and AD respectively of a parallelogram ABCD.

To Prove: ar(ΔAPB) = ar(ΔBQC).
Proof: ∵ ΔAPB and || gm ABCD are on the same base AB and between the same parallels AB and DC.
therefore space space ar left parenthesis increment APB right parenthesis equals 1 half ar left parenthesis parallel to space gm space ABCD right parenthesis space space space space space space space space space space space space space space space.... left parenthesis 1 right parenthesis
∵ ΔBQC and || gm ABCD are on the same base BC and between the same parallels BC and AD.
therefore space space ar left parenthesis increment BQC right parenthesis equals 1 half ar left parenthesis space parallel to space gm space ABCD right parenthesis space space space space space space space space space space space space space space space space space... left parenthesis 2 right parenthesis
From (1) and (2),
ar(ΔAPB) = ar(ΔBQC).