\input zb-basic \input zb-matheduc \iteman{ZMATH 2016e.00738} \itemau{Choate, Jon} \itemti{Angle bisectors: an algebraic approach.} \itemso{Consortium 110, 1-2 (2016).} \itemab From the text: In algebra courses students are often taught several different forms for linear equations, the slope-intercept form $y=mx+b$, the point-slope form $y-y_1=m(x-x_1)$, and the standard form $ax+by+c=0$. I would like to add a fourth form, the normal form $ax+by+c=0$ with $\sqrt{a^2+b^2}=1$. The rest of this article will use this form and some of the vector algebra that is taught in an upper level pre-calculus course to find the equations of angle bisectors and planes that bisect dihedral angles. \itemrv{~} \itemcc{G70} \itemut{analytic geometry; equations of straight lines; linear equations; normal form; angle bisectors; vectors; triangle incenter; coordinates; parametric equations; rhombus; 2-space; 3-space; equations of planes; tetrahedral; bisecting planes; in-spheres; cross products} \itemli{} \end