Question

A circle whose center is the origin passes through the point (-5,12). Which point also lies on this circle?

Answer 1

The answer is B(11, 2sqrt(12) )
proof

the main equation of the circle is   (x-x1)²+(y-y1)²=R²
where C(x1, y1) is the center 
so if the center is the origin, it is O(0,0), and the equation becomes
  (x)²+(y)²=R²
and the circle passes through the point (-5,2) so we can write 
(-5)²+12²=R², it implies R= sqrt(25+144)=sqrt(169)=13

and  for B(11, 2sqrt(12) )     11²+  (2sqrt(12))²= 121 + 48= 169= 13
it is checked.