Question

If AB is a Diameter of the circle whose centre is (2,-3) and B is (1,4), then the coordinates of A is

• A.
  (10,-3)
• B.
  (3, 10)
• C.
  (-3, 10)
• D.
  (3,-10)

Answer 1

The correct option is D

(3,-10)
Let the coordinates of point A be (x,y)

By mid- point formula,

$\frac{x+1}{2}=2\Rightarrow x+1=4\Rightarrow x=4-1\therefore x=3\frac{y+4}{2}=-3\Rightarrow y+4=-6\Rightarrow y=-6-4\therefore y=10$

So, the coordinates of point A is (3,-10).

Thus, Option (d) is correct.