//
// Orthogonal Circles intersect at 90^0: radii connecting to intersection point are perpendicular
//
public bool AreOrthognal(Circle thatCircle)
{
// Find the intersection points
Point inter1;
Point inter2;
FindIntersection(thatCircle, out inter1, out inter2);
// If the circles intersect at 0 points.
if (inter1 == null) return false;
// If the circles intersect at 1 point they are tangent
if (inter2 == null) return false;
// Create two radii, one for each circle; arbitrarily choose the first point (both work)
Segment radiusThis = new Segment(this.center, inter1);
Segment radiusThat = new Segment(this.center, inter1);
return radiusThis.IsPerpendicularTo(radiusThat);
}