Question

The co-ordinates of one end-point of a circle are $(-3,1)$ and the co-ordinates of the center of the circle are $(2,-4)$. The co-ordinates of the other end- point of the diameter are

• A. $(\frac{-1}{2},\frac{-3}{2})$
• B. $(-7,9)$
• C. $(7,-9)$
• D. $(\frac{1}{2},\frac{3}{2})$

Answer 1

The correct option is C $(7,-9)$

Let the co-ordinates of the other end point of the diameter be $(x,y)$

Then $\frac{-3+x}{2}=2$and$\frac{1+y}{2}=-4\Rightarrow -3+x=4$and$1+y=-8\Rightarrow x=7$and$y=-9$