Q.

In the given figure, DE ∥ BC, AE = a units, EC = b units, DE = x units and BC = y units. Which of the following is true

1 x=a+bay  
2 y=axa+b  
3 x=aya+b  
4 xy=ab  

Ans.

(3)

As DE∥BC

∴ AEAC=DEBC  [From BPT]

⇒aa+b=xy

⇒x(a+b)=ay⇒x=aya+b