How to find the intersection of two circles I am doing a question on coordinate geometry.
It asks to find the points of intersection of the two circles:
$\\(x+1)^2+(y-2)^2=10$
and
$\\(x-1)^2+(y-3)^2=5$
And then find the area of the triangle formed by the two points and the origin.
I am wondering how to do this - when I sketch it, it looks like the line segment joining the points of intersection is perpendicular to the line segment joining the centers, but I can't prove this, and don't know what to do with it anyway.
Any help please!

Hint: 
By subtracting the equations you get the radical line of them: $$4x+2y = 10.$$ Now plug $y =5-2x$ in to one of them and solve a quadratic equation on $x$... 
