ABCD is a parallelogram whose diagonals intersect at O. If P is any point on BO, prove that : -Maths 9th

1 Answer

Answer :

(i) Since diagonals of a parallelogram bisect each other. ∴ O is the mid - point AC as well as BD. In △ADC, OD is a median. ∴ ar(△ADO) = ar(△CDO)  [∵ A median of a triangle divide it into two triangles of equal area] (ii) Since O is the mid - point of AC ∴ OB and OP  are medians of △ABC and △APC respectively . ∴ ar(△AOB) = ar(△BOC) ---i) and  ar(△AOP) = ar(△COP)  ---ii) [∵ A median of a triangle divide it into two triangles of equal area] Subtracting (ii) and (i) , we have ar(△AOB) - ar(△AOP) = ar(△BOC) - ar(△COP)  ⇒ ar(△ABP) = (△CBP)

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