# Checking if two circles in the plane are orthogonal: is_orthogonal

### 13.16.13 Checking if two circles in the plane are orthogonal: is_orthogonal

See Section 14.13.5 for checking for orthogonality in three-dimensional geometry.

The is_orthogonal command determines whether or not two lines or circles are orthogonal.

- is_orthogonal takes two arguments:
  C1,C2, two objects, both lines or both circles.
- is_orthogonal(C1,C2) returns 1 if C1 and C2 are orthogonal and returns 0 otherwise.

#### Examples.

- Input:
  is_orthogonal(line(0,1+i),line(i,1))
  Output:

  1

- Input:
  is_orthogonal(line(2,i),line(0,1+i))
  Output:

  0

- Input:
  is_orthogonal(circle(0,1+i),circle(2,1+i))
  Output:

  1

- Input:
  is_orthogonal(circle(0,1),circle(2,1))
  Output:

  0