In a trapezium ABCD, O is the point of intersection of AC and BD, AB ∥ CD and AB=2CD. If the area of ΔAOB=84cm2, find the area of ΔCOD.
Open in App
Solution
ABCD is a trapezium in which, AB ∥ CD and diagonals AC and BD intersect each other at O. In ΔAOB and ΔCOD we have ∠1=∠2 [Alt ∠s] ∠3=∠4 [vert opp. \angle s\therefor \Delta AOB \sim \Delta COD$ [By AA criterion of similarity] ⇒ar(ΔAOB)ar(ΔCOD)=(2CD)2(CD)2 [AB = 2CD (Given)] =4CD2CD2=4 =84ar(ΔCOD)=4; ∴ar(ΔCOD)=84+4=21cm2