### 26.7.4 Equilateral triangles in the plane

See Section 27.6.4 for equilateral triangles in space.

The equilateral_triangle command creates equilateral triangles.

- equilateral_triangle takes two mandatory arguments and one optional argument:
  - A,B, two points.
  - Optionally, var, a variable name.
- equilateral_triangle(A,B ⟨,var ⟩) returns and draws the equilateral ABC, where AB to AC is counterclockwise.

  With the argument var, C will be assigned to var.

#### Examples

equilateral_triangle(1/2+i/2,4+i)

equilateral_triangle(1/2+i/2,4+i,C)

evalc(affix(C))

−2 | √ |
3
| +18
8
| + |
i | ⎛ ⎜ ⎝ | 14 | √ |
3
| +6 | ⎞ ⎟ ⎠
8