Answers and Explanations

COORDINATE GEOMETRY FOLLOW-UP TEST

1 . E

The graph   of  x^2     +   y^2     =    25     is  a   circle  centered    at  the origin  with    a   radius  of

5. The square of that radius must equal the sum of the squares of the
   coordinates of any point on the circle. This happens on the axes.

And x   and y   are both    integers    at  these   points  as  well.