Q: 15 Diagonals AC and BD of a quadrilateral ABCD intersect at O in such a way that . Prove that ABCD is a trapezium.
We have,
ABCD is a quadrilateral and diagonals AC and BD intersect at O such that ar(AOD) = ar (
BOC) ...........(i)
Now, add ar (BOA) on both sides, we get
ar(AOD) + ar (
BOA) = ar (
BOA) + ar (
BOC)
ar (ABD) = ar (
ABC)
Since the ABC and
ABD lie on the same base AB and have an equal area.
Therefore, AB || CD
Hence ABCD is a trapezium.