Straight Line Question 85

Question: The image of the point (4, - 3) with respect to the line y = x is[RPET 2002]

Options:

A)15/8

B)25/4

C)25/8

D)25/16

Show Answer

Answer:

Correct Answer: D

Solution:

  • Here $ L\equiv x+y=2 $ and $ {L}’\equiv 2x-2y=1 $ . Equation of y-axis is $ x=0 $ Hence the vertices of the triangle are $ A(0,2),B( 0,-\frac{1}{2} ) $ and $ C( \frac{5}{4},\frac{3}{4} ) $ . Therefore, the area of the triangle is $ \frac{1}{2}| \begin{matrix} 0 & 2 & 1 \\ 0 & -\frac{1}{2} & 1 \\ \frac{5}{4} & \frac{3}{4} & 1 \\ \end{matrix} |=\frac{25}{16} $ .