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Constructions

Question
CBSEENMA9002886

Show that the line segment joining the mid-points of a pair of opposite sides of a parallelogram divides it into two equal parallelograms.

Solution
Given: A parallelogram ABCD in which M and N are the mid-points of a pair of its opposite sides AB and DC respectively.

To Prove: ar(|| gm AMND) = ar(|| gm MBCN). Proof: ∵ ABCD is a || gm
therefore space space space space space AB space equals space DC space space space and space space AB space parallel to space DC
rightwards double arrow space space space space space 1 half AB equals 1 half DC space and space AM space parallel to space DN
rightwards double arrow space space space space space AM equals DN space space and space space AM space parallel to space DN
rightwards double arrow space space space space space square AMND space is space straight a space parallel to space gm.

Similarly, we can prove that □MBCN is a parallelogram.
∵ || gm AMND and || gm MBCN are on equal bases AM and MB (∵ M is the mid-point of AB) and between the same parallels AB and DC.
∴ ar(|| gm AMND) = ar(|| gm MBCN).