The circumcenter of a right angled triangle is midpoint of the hypotenuse side.
Determine the midpoint of the hypotenuse.

For y coordinate,

So, circumcenter of triangle is,
This might be wrong but, 320.
I used the formula for simple interest which is I=Prt, thus giving me this:
I = 1000 (.016) (20)
Hope this helps at all!