ABCD is a trapezium with parallel sides AB=a and DC=b. If E and F are mid-points of non-parallel sides AD and BC respectively, then the ratio of areas of quadrilaterals ABFE and EFCD is:
Clearly, EF=AB+DC2=a+b2
Area of Trapezium =12(Sum of parallel sides)×h
Let h be the height as shown in figure, then
ar(Trap.ABFE):ar(Trap.EFCD)
⇒12[a+a+b2]×h:12[b+a+b2]×h
⇒ 2a+a+b2:2b+a+b2
⇒ 3a+b:a+3b
Hence, this is the required ratio.