Bisectrix of a triangle in tikz I'm trying to make a triangle with its bisectrices. I made the first bisectrix with the command: \begin{tikzpicture}[scale=3] \coordinate (A) at (1,0); \coordinate (B) at (0,0); \coordinate (C) at (30:1cm); \coordinate (D) at (15:1cm); \draw (A) -- (B) -- (C); \draw (A) -- (B) -- (D); \fill (0,0) circle (0.0 cm) node[ left ]{B}; \fill (1.0,0.0) circle (0.0 cm) node[ right ]{A}; \fill (0.86,.5) circle (0.0 cm) node[ right ]{C}; \fill (0.96,.26) circle (0.0 cm) node[ right ]{D}; \draw [help lines] (0,0) grid (1,1); \end{tikzpicture} But, I can't do the other bisectrices. When I try use the same command, the commands take me away from desire result. Someone can help me? Thanks!

One approach to drawing the bisector of $\angle BAC$ with tikz is to define two coordinates, say $AtB$ and $AtC$ on $AB$ and $AC$, respectively, at equal distance from $A$. Then one computes the midpoint of the segment connecting $AtB$ to $AtC$; finally, one draws the line from $A$ to that midpoint. The code may look like this:


\coordinate (AtB) at ($ (A) !1cm! (B) $);
\coordinate (AtC) at ($ (A) !1cm! (C) $);
\coordinate (BACb) at ($ (AtB) !0.5! (AtC) $);
\draw (A) -- (BACb);