The incircle ic of triangle T is the circle inscribed inside the triangle.

If the optional argument is given and is of the form 'centername' = cn where cn is name, cn will be the name of the center of ic.

For a detailed description of the incircle ic, use the routine detail (i.e., detail(ic))

Note that the routine only works if the vertices of the triangle are known.

$\mathrm{with}\left(\mathrm{geometry}\right)\:$

$\mathrm{triangle}\left(T\,\left[\mathrm{point}\left(A\,0\,0\right)\,\mathrm{point}\left(B\,2\,0\right)\,\mathrm{point}\left(C\,1\,3\right)\right]\right)\:$

$\mathrm{incircle}\left(\mathrm{inc}\,T\,'\mathrm{centername}'=o\right)$

$\mathrm{inc}$

$\mathrm{detail}\left(\mathrm{inc}\right)$

assume that the names of the horizontal and vertical axes are _x and _y, respectively

$\begin{array}{ll}\text{name of the object}& \mathrm{inc}\\ \text{form of the object}& \mathrm{circle2d}\\ \text{name of the center}& o\\ \text{coordinates of the center}& \left[1\,\frac{3}{\sqrt{10}+1}\right]\\ \text{radius of the circle}& \frac{3}{\sqrt{10}+1}\\ \text{equation of the circle}& 1+{\mathrm{\_x}}^2+{\mathrm{\_y}}^2-2\mathrm{\_x}-\frac{6\mathrm{\_y}}{\sqrt{10}+1}=0\end{array}$