question_answer

In a parallelogram ABDC, the coordinates of A, B and C are respectively (1, 2), (3, 4) and (2, 5) then the equation of the diagonal AD is [JEE  Main Online Paper (Held on 11-jan-2019 Evening)]

A) \[5x-3y+1=0\]                          

B) \[3x-5y+7=0\]

C) \[5x+3y-11=0\]

D) \[3x+5y-13=0\]

Correct Answer: A

Solution :

Since, ABDC is a parallelogram. \[\therefore \]Coordinates of D are C4, 7). \[\therefore \]Equation of AD is  \[y-7=\frac{7-2}{4-1}(x-4)\] \[\Rightarrow \]\[5x-3y+1=0\]